TECHNICAL  INSTRUCTION  SERIES 


cow  J 


DY 


W 11/ ITERS 

FOR] 

TOT  [its 


PAU  a  .<(.  iASlUCK 


I 

SSHftS  j 


HANDICRAFT  SERIES. 

A  Series  of  Practical  Manuals. 

Edited  by  PAUL  N.  HASLUCK,  Editor  of  "Work,"  "Technical  Instruction 

Series,"  etc. 
Price  50  cts.  each,  postpaid. 


House  Decoration.     Comprising  Whitewashing,  Paperhanging,  Painting,  etc. 
With  79  Engravings  and  Diagrams. 
Contents. — Colour  and  Paints.    Pigments,  Oils,  Driers,  Varnishes,  etc.    Tools  used  by 
Painters.    How  to  Mix  Oil  Paints.    Distemper  or  Tempera  Painting.  Whitewashing 
and  _  Decorating  a  Ceiling.    Painting  a  Room.    Papering  a  Room.    Embellishment  of 

] 


1 
i 


FRANKLIN  INSTITUTE  LIBRARY 

PHILADELPHIA,  PA. 


HANDICRAFT  SERIES  {Continued). 


Building  Model  Boats.    With  16b  Engravings  and  Diagrams. 

Contents. — Building  Model  Yachts.  Rigging  and  Sailing  Model  Yachts.  Making  and 
Fitting  Simple  Model  Boats.  Building  a  Model  Atlantic  Liner.  Vertical  Engine  for  a 
Model  Launch.  Model  Launch  Engine  with  Reversing  Gear.  Making  a  Show  Case  for 
a  Model  Boat. 

Electric  Bells,  How  to  Make  and  Fit  Them,    With  162  Engravings  and  Diagrams. 

Contents. — The  Electric  Current  and  the  Laws  that  Govern  it.  Current  Conductors 
used  in  Electric-Bell  Work.  Wiring  for  Electric  Bells.  Elaborated  Systems  of  Wiring; 
Burglar  Alarms.  Batteries  for  Electric  Bells.  The  Construction  of  Electric  Bells,  Pushes, 
and  Switches.    Indicators  for  Electric-Bell  Systems. 

Bamboo  Work.    With  177  Engravings  and  Diagrams. 

Contents. — Bamboo:  Its  Sources  and  Uses.  How  to  Work  Bamboo.  Bamboo  Tables. 
Bamboo  Chairs  and  Seats.  Bamboo  Bedroom  Furniture.  Bamboo  Hall  Racks  and  Stands. 
Bamboo  Music  Racks.  Bamboo  Cabinets  and  Bookcases.  Bamboo  Window  Blinds. 
Miscellaneous  Articles  of  Bamboo.    Bamboo  Mail  Cart. 

Taxidermy.    With  108  Engravings  and  Diagrams. 

Contents. — Skinning  Birds.  Stuffing  and  Mounting  Birds.  Skinning  and  Stuffing 
Mammals.  Mounting  Animals'  Horned  Heads:  Polishing  and  Mounting  Horns.  Skin- 
ning, Stuffing,  and  Casting  Fish.  Preserving,  Cleaning,  and  Dyeing  Skins.  Preserving 
Insects,  and  Birds'  Eggs.    Cases  for  Mounting  Specimens. 

Tailoring.    With  180  Engravings  and  Diagrams. 

Contents. — Tailors'  Requisites  and  Methods  of  Stitching.  Simple  Repairs  and  Press- 
ing. Relining,  Repocketing,  and  Recollaring.  How  to  Cut  and  Make  Trousers.  How 
to  Cut  and  Make  Vests.  Cutting  and  Making  Lounge  and  Reefer  Jackets.  Cutting  and 
Making  Morning  and  Frock  Coats. 

Photographic  Cameras  and  Accessories.     Comprising  How  to  Make  Cameras, 
Dark  Slides,  Shutters,  and  Stands.    With  160  Illustrations. 
Contents. — Photographic  Lenses  and  How  to  Test  them.  Modern  Half-plate  Cameras. 
Hand  and  Pocket  Cameras.    Ferrotype  Cameras.    Stereoscopic  Cameras.  Enlarging 
Cameras.    Dark  Slides.    Cinematograph  Management. 

Optical  Lanterns.  Comprising  The  Construction  and  Management  of  Optical 
Lanterns  and  the  Making  of  Slides.  With  160  Illustrations. 
Contents. — Single  Lanterns.  Dissolving  View  Lanterns.  Illuminant  for  Optical  Lan- 
terns. Optical  Lantern  Accessories.  Conducting  a  Lime-light  Lantern  Exhibition.  Ex- 
periments with  Optical  Lanterns.  Painting  Lantern  Slides.  Photographic  Lantern 
Slides.    Mechanical  Lantern  Slides.    Cinematograph  Management. 

Engraving  Metals.    With  Numerous  Illustrations. 

Contents. — Introduction  and  Terms  used.  Engravers'  Tools  and  their  Uses.  Ele- 
mentary Exercises  in  Engraving.  Engraving  Plate  and  Precious  Metals.  Engraving 
Monograms.  Transfer  Process  of  Engraving  Metals.  Engraving  Name  Plates.  En- 
graving Coffin  Plates.  Engraving  Steel  Plates.  Chasing  and  Embossing  Metals.  Etch- 
ing Metals. 

Basket  Work.    With  189  Illustrations. 

Contents. — Tools  and  Materials.  Simple  Baskets.  Grocer's  Square  Baskets.  Round 
Baskets.  Oval  Baskets.  Flat  Fruit  Baskets.  Wicker  Elbow  Chairs.  Basket  Bottle- 
casings.  Doctors'  and  Chemists'  Baskets.  Fancy  Basket  Work.  Sussex  Trug  Basket. 
Miscellaneous  Basket  Work.  Index. 

Bookbinding.    With  125  Engravings  and  Diagrams. 

Contents. — Bookbinders'  Appliances.  Folding  Printed  Book  Sheets.  Beating  and 
Sewing.  Rounding,  Backing,  and  Cover  Cutting.  Cutting  Book  Edges.  Covering 
Books.  Cloth-bound  Books,  Pamphlets,  etc.  Account  Books,  Ledgers,  etc.  Coloring, 
Sprinkling,  and  Marbling  Book  Edges.  Marbling  Book  Papers.  Gilding  Book  Edges. 
Sprinkling  and  Tree  Marbling  Book  Covers.  Lettering,  Gilding,  and  Finishing  Book 
Covers.  Index. 

Bent  Iron  Work.    Including  Elementary  Art  Metal  Work.    With  269  Engravings 
and  Diagrams. 

Contents. — Tools  and  Materials.  Bending  and  Working  Strip  Iron.  Simple  Exercises 
in  Bent  Iron.  Floral  Ornaments  for  Bent  Iron  Work.  Candlesticks.  Hall  Lanterns. 
Screens,  Grilles,  etc.  Table  Lamps.  Suspended  Lamps  and  Flower  Bowls.  Photo- 
graph Frames.    Newspaper  Rack.    Floor  Lamps.    Miscellaneous  Examples.  Index. 

Photography.    With  Numerous  Engravings  and  Diagrams. 

Contents. — The  Camera  and  its  Accessories.  The  Studio  and  the  Dark  Room.  Plates. 
Exposure.  Developing  and  Fixing  Negatives.  Intensification  and  Reduction  of  Nega- 
tives. Portraiture  and  Picture  Composition.  Flash-light  Photography.  Retouching 
Negatives.  Processes  of  Printing  from  Negatives.  Mounting  and  Finishing  Prints. 
Copying  and  Enlarging.    Stereoscopic  Photography.    Ferrotype  Photography. 

DAVID  McKAY,  Publisher,  Washington  Square,  Philadelphia. 


HANDICRAFT  SERIES  {Continued). 


Upholstery.    With  162  Engravings  and  Diagrams. 

Contents. — Upholsterers'  Materials.  Upholsterers*  Tools  and  Appliances.  Webbing, 
Springing,  Stuffing,  and  Tufting.  Making  Seat  Cushions  and  Squabs.  Upholstering  an 
Easy  Chair.  Upholstering  Couches  and  Sofas.  Upholstering  Footstools,  Fenderettes, 
etc.  Miscellaneous  Upholstery.  Mattress  Making  and  Repairing.  Fancy  Upholstery. 
Renovating  and  Repairing  Upholstered  Furniture.  Planning  and  Laying  Carpets  and 
Linoleum.  Index. 

Leather  Working.    With  162  Engravings  and  Diagrams. 

Contents. — Qualities  and  Varieties  of  Leather.  Strap  Cutting  and  Making.  Letter 
Cases  and  Writing  Pads.  Hair  Brush  and  Collar  Cases.  Hat  Cases.  Banjo  and  Man- 
doline Cases.  Bags.  Portmanteaux  and  Travelling  Trunks.  Knapsacks  and  Satchels. 
Leather  Ornamentation.  Footballs.  Dyeing  Leather.  Miscellaneous  Examples  of 
Leather  Work.  Index. 

Harness  Making.    With  197  Engravings  and  Diagrams. 

Contents. — Harness  Makers'  Tools.  Harness  Makers'  Materials.  Simple  Exercises  in 
Stitching.  Looping.  Cart  Harness.  Cart  Collars.  Cart  Saddles.  Fore  Gear  and  Leader 
Harness.  Plough  Harness.  Bits,  Spurs,  Stirrups,  and  Harness  Furniture.  Van  and  Cab 
Harness.  Index. 

Saddlery.    With  99  Engravings  and  Diagrams. 

Contents. — Gentleman's  Riding  Saddle.  Panel  for  Gentleman's  Saddle.  Ladies'  Side 
Saddles.  Children's  Saddles  or  Pilches.  Saddle  Cruppers,  Breastplates,  and  other 
Accessories.  Riding  Bridles.  Breaking-down  Tackel.  Head  Collars.  Horse  Clothing. 
Knee-caps  and  Miscellaneous  Articles.  Repairing  Harness  and  Saddlery.  Re-lining 
Collars  and  Saddles.    Riding  and  Driving  Whips.    Superior  Set  of  Gig  Harness.  Index. 

Knotting  and  Splicing,  Ropes  and  Cordage.   With  208  Engravings  and  Diagrams. 

Contents. — Introduction.  Rope  Formation.  Simple  and  Useful  Knots.  Eye  Knots, 
Hitches  and  Bends.  Ring  Knots  and  Rope  Shortenings.  Ties  and  Lashings.  Fancy 
Knots.  Rope  Splicing.  Working  Cordage.  Hammock  Making.  Lashings  and  Ties  for 
Scaffolding.    Splicing  and  Socketing  Wire  Ropes.  Index. 

Beehives  and  Beekeepers'  Appliances.    With  155  Engravings  and  Diagrams. 

Contents. — Introduction.  A  Bar-Frame  Beehive.  Temporary  Beehive.  Tiering  Bar- 
Frame  Beehive.  The  "  W.  B.  C."  Beehive.  Furnishing  and  Stocking  a  Beehive.  Obser- 
vatory Beehive  for  Permanent  Use.  Observatory  Beehive  for  Temporary  Use.  Inspection 
Case  for  Beehives.  Hive  for  Rearing  Queen  Bees.  Super-Clearers.  Bee  Smoker. 
Honey  Extractors.    Wax  Extractors.    Beekeepers'  Miscellaneous  Appliances.  Index. 

Electro-Plating.    With  Numerous  Engravings  and  Diagrams. 

Contents.— Introduction.  Tanks,  Vats,  and  other  Apparatus.  Batteries,  Dynamos, 
and  Electrical  Accessories.  Appliances  for  Preparing  and  Finishing  Work.  Silver- 
Plating.  Copper-Plating.  Gold-Plating.  Nickel-Plating  and  Cycle-Plating.  Finishing 
Electro-Plated  Goods.    Electro-Plating  with  Various  Metals  and  Alloys.  Index. 

Clay  Modelling  and  Plaster  Casting.    With  153  Illustrations. 

Contents. — Drawing  for  Modellers.  Tools  and  Materials  for  Clay  Modelling.  Clay  Model- 
ling. Modelling  Ornament.  Modelling  the  Human  Figure.  Waste-Moulding  Process  of 
Plaster  Casting.  Piece-Moulding  and  Gelatine-Moulding.  Taking  Plaster  Casts  from 
Nature.  Clay  Squeezing  or  Clay  Moulding.  Finishing  Plaster  Casts.  Picture  Frames 
in  Plaster.  Index. 

Violins  and  other  Stringed  Instruments.    With  about  180  Illustrations. 

Contents. — Materials  and  Tools  for  Violin  Making.  Violin  Moulds.  Violin  Making. 
Varnishing  and  Finishing  Violins.  Double  Bass  and  a  Violoncello.  Japanese  One-string 
Violin.  Mandolin  Making.  Guitar  Making.  Banjo  Making.  Zither  Making.  Dulcimer 
Making.  Index. 

Glass  Writing,  Embossing,  and  Fascia  Work.  (Including  the  Making  and  Fixing 
of  Wood  Letters  and  Illuminated  Signs.)  With  129  Illustrations. 
Contents. — Plain  Lettering  and  Simple  Tablets.  Gold  Lettering.  Blocked  Letters. 
Stencil  Cutting.  Gold  Etching.  Embossing.  French  or  Treble  Embossing.  Incised 
Fascias,  Stall-plates,  and  Grained  Background.  Letters  in  Perspective;  Spacing  Letters. 
Arrangement  of  Wording  and  Colors.  Wood  Letters.  Illuminated  Signs.  Temporary 
Signs  for  Windows.  Imitation  Inlaid  Signs.  Imitation  Mosaic  Signs.  Specimen  Alpha- 
bets. Index. 

Other  New  Volumes  in  Preparation. 

DAVID  McKAY,  Publisher,  Washington  Square,  Philadelphia. 


COLOURING  MATTERS  FOR 
DYEING  TEXTILES 


WITH  NUMEROUS  ENGRAVINGS  AND  DIAGRAMS 


BY 

PROFESSOR   J.   J.   HUMMEL,  E.O.S. 

LATE  DIRECTOR  OF  THE  DYEING  DEPARTMENT  OF  THE  YORKSHIRE  COLLEGE 
AND  LEEDS  UNIVERSITY 


NEW  AND   REVISED  EDITION 


EDITED  BY 


PAUL    K  HASLUCK 


HONOURS  MEDALLIST  IN  TECHNOLOGY 
iEDTT^OR,  OF       \V,ORK  'q  AND,  "  £U ILDTNG  W(ORLD ETC.  j  ETC. 


\    \  1  PRlIADELFHjJ  1 

DAVID    McKAY,  Publisher 

610,  SOUTH  WASHINGTON  SQUARE 
1906 


PREFACE. 


Colouring  Matters  for  Dyeing  Textiles  contains,  in  a 
form  convenient  for  everyday  use,  a  comprehensive  treatise 
on  the  subject.  The  contents  of  this  manual  are  based 
on  the  highly  esteemed  book  written  by  the  late  Dr.  J.  J. 
Hummel,  F.C.S.,  Professor  and  Director  of  the  Dyeing  Depart- 
ment of  the  Yorkshire  College,  Leeds. 

Without  omitting  any  essential  part  of  the  original  work 
the  matter  has  been  revised  and  brought  up  to  date  by  Mr. 
A.  R.  Foster,  Consulting  Textile  Expert,  City  and  Guilds 
Honours  Medallist.  Needless  to  say  many  changes  have  taken 
place  since  the  previous  edition  was  published,  and  whilst  the 
new  processes  and  appliances  have  been  incorporated,  the  older 
methods  which  are  still  in  vogue  in  less  progressive  works, 
have  been  retained  and  revised.  In  this  manner  the  manual 
has  been  made  valuable,  not  only  to  the  student,  but  all 
employed  in  bleaching,  finishing,  and  dyeing  works.  It  has, 
however,  not  been  considered  advisable  to  attempt  to  cope 
with  all  the  new  dyestufTs,  as  these  are  now  numbered  by 
thousands,  and  are  being  added  to  weekly.  It  has  been  deemed 
sufficient  to  give  examples  of  each  kind,  as  many  of  the  new 
colours  are  simply  mixtures. 

Readers  who  may  desire  additional  information  respecting 
special  details  of  the  matters  dealt  with  in  this  book,  or  in- 
structions on  any  kindred  subjects,  should  address  a  question 
to  The  Editor  of  Work,  La  Belle  Sauvage,  EC,  so  that  it  may 
be  answered  in  the  columns  of  that  journal. 

P.  N.  HASLUCK. 

La  Belle  Sauvage,  London, 
November,  1906. 


1£096 


CONTENTS. 


CHAPTER  PAGE 

I — Indigo  Colouring  Matters   9 

II.— Logwood  Colouring  Matters   31 

III.  — Natural  Red  and  Yellow  Colouring  Matters  .       .  47 

IV.  — Aniline  Colouring  Matters       .       .      .      .       .  50 
V. — Quinoline  and  Phenol  Colouring  Matters       .      .  72 

VL— Azo  Colouring  Matters   84 

VII. — Anthracene  Colouring  Matters   96 

VIII.— Chrome  Yellow,   Iron    Buff   Manganese  Brown, 

Prussian  Blue   127 

IX. — Method  of  Devising  Experiments  in  Dyeing  .  .132 

X. — Estimation  of  the  Value  of  Colouring  Matters     .  150 

Index  ,      ,,       ,       .       ,       .      ,.       .       .       .  155 


LIST   OF  ILLUSTRATIONS. 

FIG.  PAGH 

1.  —  Indigo  Grinding  Mill  10 

2.  — Enlarged  View  of  one  Dyeing  Cistern  and  Accessories  .  14 

3.  — Indigo  Vat  18 

4.  — Apparatus  for  Preparing  Hydrosulphite  Vat  Liquor         .  22 

5.  — Aniline  Black  Dyeing  Machine   .        .        .        .        .  .67 

6.  — Turkey-red  Yarn  wringing  Machine    .....  98 

7.  — Tramping  Machine  for  Turkey-red  Yarn    .       .        .  .100 

8.  — Clearing  Boiler:  Elevation   103 

9.  — Clearing  Boiler:  Plan  104 

10.  — Hydraulic  Press  105 

11.  — Oil-padding  Machine  108 

12.  — Liquor-padding  Machine :  Section       .       .       .       .  .109 

13.  — Turkey-red  Stove:  Ground  Plan  110 

14.  — Turkey-red  Stove  :  Sectional  Elevation  .  .  .  .110 
K>.  —  Steaming-chest  for  Turkey-red  Yarn  .       .       .       .  .114 

16.  — Continuous  Steaming-chest:  Plan        .       .       .       .       .  116 

17.  — Continuous  Steaming-chest:  Elevation        ....  116 

18.  — Experimental  Dyeing  Apparatus:  Plan       ....  140 

19.  — Experimental  Dyeing  Apparatus  :  Elevation       .       .  .140 

20.  — Experimental  Dyeing  Apparatus  :  Section  ....  140 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/colouringmattersOOhumm 


COLOURING  MATTERS  FOR 
DYEING  TEXTILES. 

CHAPTER  L 

INDIGO    COLOURING  MATTERS. 

Theory  of  Indigo  Dyeing. — This  valuable  colouring  matter 
is  obtained  from  the  leaves  of  various  species  of  Indigofera 
(I.  tinctoria,  I.  disperma,  etc.),  which  are  cultivated 
largely  in  India.  It  is  also  manufactured  synthetically — 
whilst  in  addition  to  the  artificial  Indigo  giving  the  usual 
blue  shades  and  dyed  in  the  same  manner  as  natural  In- 
digo, there  is  Thio  Indigo  Red  B  (Kalle)  giving  pink 
shades.  The  chief  method  employed  in  dyeing  with  Indigo 
is  founded  on  the  property  it  possesses  of  being  converted 
under  the  influence  of  reducing  agents  (bodies  capable  of 
yielding  nascent  hydrogen)  into  indigo-white  which  is 
soluble  in  alkaline  solutions.  When  textile  materials  are 
steeped  for  a  short  time  in  such  solutions,  and  then  ex- 
posed to  the  air,  they  become  dyed  blue  in  consequence  of 
the  re-oxidation  of  the  indigo-white  absorbed  by  the  fibres, 
and  the  precipitation  of  insoluble  indigotin  thereupon, 
and,  indeed,  in  such  a  manner  as  to  be  indelibly  fixed. 
This  "  indigo-vat  n  method  is  applicable  to  all  textile 
fibres,  and  gives  permanent  colours. 

Another  method  of  dyeing  with  Indigo,  but  one  which 
yields  fugitive  colours,  and  is  applicable  only  to  the 
animal  fibres,  depends  on  the  fact  that  Indigo  treated 
with  strong  sulphuric  acid  becomes  changed  into  soluble 
indigotin-di-sulphonic  acid  (Indigo  Extract).  Animal 
fibres  attract  and  are  dyed  with  this  compound  when  sim- 
ply steeped  in  its  hot  and  slightly  acidified  solutions. 

Yat-blue  is  largely  employed,  particularly  in  woollen 
dyeing,  as  the  blue  part  of  compound  shades,  as  browns, 
drabs,  etc.    The  same  may  be  said  of  Indigo  Extract  or 


10    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Indigo  Carmine  blue,  with  regard  to  wool  and  silk  dye- 
ing. Indeed,  this  colouring  matter  possesses  certain 
advantages  over  the  majority  of  blue  colouring  matters. 
It  can  be  associated  with  other  acid  colouring  matters, 
and  it  dyes  very  level  shades.  Its  only  drawback  is  its 
extremely  fugitive  character. 

Indigo  Grinding  Mills. — One  of  the  first  necessities 
in  employing  Indigo  in  dyeing  is  to  have  it  thoroughly 
well  ground.    When  required  for  making  Indigo  Carmine 


Fig.  1. — Indigo  Grinding  Mill. 


it  must  be  ground  in  the  dry  state,  but  for  the  indigo-vat 
it  may  be  mixed  with  water,  which  considerably  facilitates 
the  grinding. 

The  oldest  form  of  grinding  machine  is  the  stamping 
mill,  provided  with  an  arrangement  for  passing  the 
ground  Indigo  through  fine  sieves.  The  mills  now  gener- 
ally employed  consist  of  cast-iron  vessels,  in  which  the 
Indigo  is  ground  either  by  the  rolling  of  heavy  cannon 
balls  or  of  iron  cylinders.  The  ball  mills  are  said  to  give 
the  finest  powder ;  the  cylinder  mills  the  greatest  yield 
within  a  given  period.  Fig.  1  represents  a  section  of 
one  of  the  best  forms  of  ball  mills.  It  consists  of  a  strong 
iron  box  enclosing  several  heavy  cannon  balls,  which  are 
pushed  round  by  means  of  a  pair  of  revolving  arms. 
Sometimes  the  bottom  of  the  box  is  flat,  and  heavy  blocks 
of  sand-stone  are  substituted  for  balls. 

Application  of  Indigo  to  Cotton. — The  fermentation 


INDIGO   COLOURING  MATTERS. 


n 


vats  so  much  used  in  dyeing  wool  with  Indigo  are  never 
employed  for  cotton,  since  it  is  essential  that  this  should  be 
dyed  in  the  cold  to  obtain  the  best  colour;  and,  further, 
it  permits  the  use  of  vats,  in  which  the  reduction  of  the 
Indigo  is  effected  in  a  manner  more  under  control.  Ac- 
cording to  the  reducing  agents  employed,  the  indigo-vats 
used  for  cotton  may  be  named  as  follows  :  The  ferrous 
sulphate  vat,  the  zinc  powder  vat,  the  hydrosulphite  vat. 

Ferrous  Sulphate  Vat. — This  vat,  usually  known  as  the 
lime  and  copperas  vat,  is  the  oldest  and  perhaps  the  one 
still  most  commonly  employed.  The  vats  or  dye-vessels  are 
rectangular  tanks  of  wood,  stone,  or  cast-iron.  The  size 
varies  according  to  the  material  to  be  dyed ;  for  calico 
they  are  generally  2  metres  =  6  ft.  6  in.  deep,  2  metres 
long,  and  about  1  metre  broad,  while  for  yarn-dyeing 
they  are  somewhat  smaller. 

In  order  to  economise  the  Indigo  as  much  as  possible, 
the  vats  are  generally  worked  in  sets  of  ten. 

The  materials  used  in  preparing  this  vat  are: — 


Cloth.  Yarn. 

Water      .       .     4,000  litres  or  750  litres.  = 

Indigo      .       .        40  kilos.  ,..     4  kilos.  = 

Ferrous  sulphate  60-80  „  6-8    ,,  = 

Slaked  lime  (dry)  50-100  5-10,,  = 


Cloth.  Yarn. 
S80-3  gals,  or      165D  gals. 

88-1  lb.  8-8  lb. 

132-2-176-3  „  ,,  13-2-17-6  ,, 
110-2-220-4   „      „  11-0-22-0  „ 


The  chemical  changes  which  take  place  during  the 
"  setting  77  or  preparation  of  the  vat  may  be  briefly 
summed  up  as  follows  :  The  lime  decomposes  the  ferrous 
sulphate,  and  produces  ferrous  hydrate,  which  in  the 
presence  of  the  indigo  rapidly  decomposes  the  water,  and 
becomes  changed  into  ferric  hydrate,  while  the  liberated 
hydrogen  at  once  combines  with  the  indigotin  to  form 
indigo-white.  This  last  substance  combines  with  the  ex- 
cess of  lime  present,  and  at  once  enters  into  solution. 
These  reactions  may  be  expressed  by  the  following  chemi- 
cal formulse  : — 

FeS04  +  Ca(OH)2  =  CaS04  +  Fe(OH)2. 

Ferrous  sulphate.  Lime.       Calcium  sulphate.    Ferrous  hydrate. 

2[Fe(OH)2]  +  2H20  =  Fe2(OH)0  +  H3. 

Ferrous  hydrate.  Ferric  hydrate. 

ClcH10N2O2  +  H2  .  0MHwNA- 

Indigotin.  Indigo-white. 

The  order  in  which  the  ingredients  are  added  is  of 


12    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


comparatively  little  moment,  and  varies  with  different 
dyers.  The  most  rational  method,  however,  is  to  fill  the 
vat  with  water  and  add  first  the  ground  Indigo  and  milk 
of  lime;  after  raking  up  well,  a  solution  of  ferrous  sul- 
phate is  added,  and  the  whole  mixture  is  systematically 
raked  up  at  frequent  intervals  during  twenty-four  hours, 
until  the  Indigo  is  thoroughly  reduced.  With  this  plan 
the  actual  reducing  agent,  ferrous  hydrate,  is  always  in 
the  presence  of  an  excess  of  Indigo,  and  the  indigo-white, 
the  moment  it  is  produced,  is  dissolved  in  the  excess  of 
lime.  Owing  to  the  mixture  becoming  rapidly  thick  and 
difficult  to  stir  well,  the  more  usual  plan  adopted  is  to 
put  in  the  Indigo  and  ferrous  sulphate  first,  and  to  add 
the  milk  of  lime  gradually.  Lime  is  used  in  preference 
to  caustic  soda,  because  the  vat  thus  produced  dyes  the 
cotton  more  readily ;  and  owing  to  the  film  of  calcium 
carbonate  which  forms  on  its  surface,  the  indigo-white  in 
the  liquor  beneath  is  less  liable  to  become  oxidised. 

The  ferrous  sulphate  employed  should  be  as  pure  as 
possible.  Any  admixture  of  copper  sulphate  is  injurious 
because  of  its  oxidising  influence,  while  the  presence  of 
aluminium  sulphate  and  basic  ferric  sulphate,  since  these 
are  quite  inert  as  reducing  agents,  causes  loss  of  so  much 
lime  as  is  required  for  their  decomposition,  besides  a 
useless  increase  of  sediment.  The  use  of  a  large  excess  of 
ferrous  sulphate  and  lime  should  also  be  avoided  for  this 
last  reason.  Ferrous  sulphate,  containing  copper  sulphate 
and  ferric  sulphate,  is  readily  purified  by  boiling  its 
solution  with  iron  turnings,  whereby  the  copper  is  precipi- 
tated, and  the  ferric  sulphate  is  partly  reduced  to  ferrous 
sulphate,  or  fully  decomposed  and  precipitated. 

A  freshly  made-up  vat  is  in  good  condition  when 
numerous  thick  dark  blue  veins  appear  on  raking  up  the 
liquor,  and  the  surface  becomes  rapidly  covered  with  a 
substantial  blue  scum  or  "  flurry. "  The  liquid  should  be 
clear,  and  of  a  brownish-amber  colour ;  if  greenish,  it 
shows  the  presence  of  unreduced  Indigo,  and  requires  a 
further  addition  of  ferrous  sulphate.  If  the  colour  is 
very  dark,  more  lime  is  required. 

At  the  end  of  every  day's  work  the  vats  should  be 
well  raked  up,  and,  according  to  their  appearance,  "  fed  77 
or  replenished  with  small  additions  of  lime  and  ferrous 


INBIGO   COLOURING  MATTERS. 


13 


sulphate.  The  rake  used  for  this  purpose  consists  of  a 
rectangular  iron  plate,  with  long  wooden  handle  attached. 

Before  dyeing,  the  flurry  should  be  carefully  removed 
with  an  iron  scoop  or  "  skimmer,"  otherwise  it  attaches 
itself  to  the  cotton,  and  causes  it  to  look  uneven  or 
spotted. 

Cotton  yarn  should  be  previously  well  boiled  with 
water,  in  order  to  make  it  dye  evenly.  When  dyeing 
light  shades  of  blue,  only  a  few  hanks  are  dyed  at  once, 
the  dipping,  turning,  and  squeezing  being  performed 
with  the  utmost  regularity.  According  to  the  depth  of 
blue  required,  the  duration  of  each  immersion  may  vary 
from  one  to  five  minutes  or  more,  and  after  wringing, 
the  hanks  are  thrown  aside,  and  allowed  to  oxidise  com- 
pletely. 

The  amount  of  indigotin  which  is  precipitated  on  the 
cotton  is  said  to  vary  with  the  duration  of  the  immersion ; 
if  this  be  true  it  would  appear  that  the  cotton  really 
attracts  indigo-white  from  the  vat  solution,  and  is  not 
dyed  merely  by  reason  of  the  indigotin  precipitated  from 
the  portion  of  liquid  absorbed  by  the  fibre.  The  most 
economical  method  is  to  dye  the  cotton  first  in  the  weaker 
vats,  and  then  to  pass  it  through  each  succeeding  stronger 
vat  until  the  desired  shade  is  obtained.  For  a  dark 
shade  the  cotton  should  not  be  put  at  once  into  a  strong 
vat,  because  it  would  be  difficult  in  this  way  to  obtain 
even  colours;  and  in  the  long  run  the  method  would 
not  be  so  economical.  For  light  shades  of  blue  only  a 
few  of  the  weaker  vats  are  needed. 

By  this  plan  of  always  using  the  weakest  vat  first,  so 
long  as  it  yields  any  colour,  each  vat  in  turn  becomes 
thoroughly  exhausted. 

After  dyeing,  the  carbonate  of  lime  which  is  deposited 
on  the  fibre  is  removed  by  rinsing  in  sulphuric  acid, 
2°-4°  Tw.(  (Sp.  Gr.  1-01-1-02).  This  operation  removes 
the  grey  tint,  and  brightens  the  colour  considerably.  The 
cotton  is  finally  dyed  in  a  moderately  strong  vat,  wrung 
out  and  dried  at  60°  C.  This  imparts  to  it  the  coppery 
lustre  so  much  admired.  It  is,  however,  entirely  super- 
ficial, and  may  be  removed  by  simply  washing  in  water. 

As  a  rule,  however,  washing  is  avoided,  since  the 
Indigo  is  apt  to  rub  off,  and  the  colour  may  look  bare  and 


14    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


wanting  in  body  and  intensity.  Vat  blues  are  improved 
in  colour  by  passing  the  goods  through  lime-water  or  a 
hot  soap  bath,  probably  because  of  the  removal  thereby 
of  some  yellow  colouring  matters. 

A  part  of  the  Mather  &  Piatt  Indigo  piece-dyeing 
machine  is  shown  in  Fig.  2,  this  portion  being  duplicated, 
trebled,  or  quadrupled  according  to  the  shade  of  indigo 
required.  The  cloth  is  taken  through  the  vats  in  a  con- 
tinuous manner,  passing  over  and  under  rollers  beneath 
the  surface  of  the  liquor  in  the  cistern  A.  After  being 
squeezed  by  rollers  b,  it  is  laid  by  the  winch  c  in  loose 


Fig.  2. — Enlarged  View  of  One  Dyeing  Cistern  and  Accessories. 


folds  upon  the  slowly  travelling  apron  d,  the  time  of 
traverse  being  such  as  to  enable  the  Indigo  to  become 
sufficiently  oxidised  upon  the  fibre.  The  cloth  then  enters 
the  next  vat,  where  the  operations  are  repeated,  and  so 
on  to  the  end  of  the  range. 

Each  vat  a  is  provided  with  a  settling  cistern  e,  having 
a  hand  pump  f,  whose  suction  pipe  goes  to  the  bottom 
of  the  dye-vat.  By  this  means  the  deposit  which  forms  in 
working  can  be  removed  before  it  has  the  opportunity  to 
stain  the  cloth  or  cause  uneven  dyeing. 

After  leaving  the  last  section,  the  pieces  are  first  rinsed 
in  cold  water  to  remove  the  loose  lime  and  Indigo  adher- 
ing superficially,  and  then  in  dilute  sulphuric  acid,  4°-8° 


INDIGO   COLOURING  MATTERS. 


L5 


Tw.  (Sp.  Gr.  1  02-1  04),  to  dissolve  off  the  calcium  car- 
bonate; they  are  finally  washed  and  dried. 

All  the  Indigo  washed  off  in  the  rinsing  pits,  as  well 
as  the  sediment  of  the  vats  themselves,  must  be  collected 
in  special  tanks,  in  order  to  recover  the  Indigo. 

According  to  F.  C.  Calvert,  the  vat  sediments  consist 
largely  of  an  insoluble  compound  of  indigotin  and  ferrous 
oxide,  forming  a  bulky  flocculent  green  precipitate. 
From  this  the  indigotin  can  be  recovered  by  decomposing 
it  in  the  cold  with  strong  hydrochloric  acid. 

Another  method  is  to  mix  the  vat  sediments  with 
water,  and  boil  with  some  cheap,  energetic  reducing  agent, 
such  as  caustic  soda  and  orpiment.  After  settling,  the 
clear  liquid  is  drawn  off,  and  oxidised  by  pumping  it  into 
a  trough  which  stands  at  a  high  level,  and  allowing 
it  to  flow  into  a  large  tank ;  here  the  precipitated 
indigotin  is  washed  and  collected. 

By  adopting  such  methods  of  recovery,  the  total  loss 
of  Indigo  may  be  reduced  to  2-3  %  of  the  original  weight 
employed. 

It  is  sometimes  the  custom  to  dye  the  cotton  or  "  bot- 
tom "  it  with  catechu  brown,  manganese  bronze  or  brown, 
or  a  blue  shade  of  aniline  black,  previous  to  introducing  it 
into  the  Indigo  vat.  By  this  means  very  deep  blue  shades 
can  be  obtained  with  less  Indigo  than  would  otherwise  be 
required. 

It  is  well  to  remember  that  when  aniline  black  is  used 
the  colour  may  be  liable  to  become  green  on  exposure. 

In  order  to  add  a  fictitious  purple  bloom  or  rich  effect 
to  the  colour,  vat  blues  are  sometimes  dyed  afterwards  or 
"  topped  "  in  a  dilute  solution  of  Methyl  Violet  or  Methy- 
lene Blue,  and  dried  without  washing ;  less  frequently 
they  are  dyed  a  logwood  blue. 

Zinc  Powder  Vat. — This  vat  is  frequently  used  on  the 
Continent,  and  also  in  Great  Britain.  It  is  founded  on 
the  fact  that  zinc,  in  the  presence  of  lime  and  Indigo, 
readily  decomposes  water,  and  combines  with  its  oxygen, 
whilst  the  liberated  hydrogen  reduces  the  indigotin  to 
indigo-white,  which  is  at  once  dissolved  by  the  excess 
of  lime  present. 

Zn  +  H20  =  ZnO  +  H2. 

The  relative  proportions  used  of  the  several  ingredients 


16    COLOURING  MATTERS  FOR  DYEING  TEXTILE 


vary  according  to  their  quality,  especially  as  regards  the 
Indigo  employed. 

The  following  may  be  considered  as  average  amounts  : 

Water       .       .       .    .    .  4,000  litres  =  880-3  gals. 

Indigo       ....  40  kilos.  =     88*1  lb. 

Zinc  powder      ...  20     ,,  —  44*0 

Slaked  lime       ...  20     „  =    44'0  „ 

The  whole  is  well  stirred  occasionally  during  18-24 
hours,  when  it  is  ready  for  use.  Lime  and  zinc  powder 
are  added  as  occasion  requires.  It  is  an  extremely  simple 
vat,  easy  to  work,  and  possesses  even  certain  advantages 
over  the  "  lime  and  copperas  "  vat.  In  the  first  place, 
the  sediment  is  reduced  to  about  one-seventh  of  that  in 
the  vat  referred  to.  Then  the  absence  of  ferrous  sulphate 
removes  the  possibility  of  the  formation  of  the  insoluble 
compound  of  indigotin  with  ferrous  oxide. 

Hence  this  vat  can  be  used  without  emptying  for  a 
much  longer  time  than  the  "  lime  and  copperas  "  vat,  and 
there  is  little  or  no  loss  of  Indigo. 

Its  chief  defect  is  that  it  is  liable  to  be  muddy  and 
frothy,  from  a  continuous  slight  disengagement  of  hydro- 
gen gas.  Hydrogen  is  not  given  off  until  the  whole  of 
the  Indigo  is  reduced,  so  that  much  froth  denotes  the 
presence  of  excess  of  zinc.  If  there  be  only  little  froth, 
it  is  removed  by  vigorously  stirring  up  the  vat  several 
times,  and  then  allowing  it  to  settle,  but  with  a  large 
excess,  a  further  addition  of  Indigo  should  be  made  before 
stirring.  After  settling  for  an  hour,  the  vat  should  be 
sufficiently  clear  for  dyeing. 

If  the  vat  is  muddy,  the  same  remedy  must  be  applied, 
since  the  cause  is  the  same.  It  is  of  no  use  to  let  it  stand 
for  a  long  time  in  the  hope  that  it  will  settle ;  the  hydrogen 
simply  accumulates,  and  the  liquid  becomes  still  more 
muddy.  The  liquid  must  be  vigorously  stirred,  in  order 
to  liberate  the  hydrogen  from  the  sediment. 

The  dyeing  should  be  completed  before  the  liquid  has 
had  time  to  become  muddy  again.  Experience  alone  can 
teach  the  exact  amount  of  zinc  powder  which  should  be 
used,  so  that  the  vat  may  be  maintained  in  an  effective 
condition,  yet  free  from  the  defects  mentioned. 

Some  dyers  find  it  an  advantage  to  add  about  12-20  kg. 
==  264-44*0  lb.  of  iron  borings.    These  act  mechanically, 


INDIGO  COLOURING  MATT  BBS, 


17 


by  presenting  a  large  and  rough  surface,  from  which  the 
hydrogen  gas  is  more  easily  liberated,  and  thus  a  clear  vat 
is  more  readily  obtained. 

Hydro  sulphite  Vat. — This  vat  is  prepared  for  cotton 
exactly  in  the  same  way  as  for  wool.  The  cotton,  however, 
should  be  dyed  in  a  cold  solution. 

Application  of  Indigo  to  Wool. — In  order  to  utilise 
the  Indigo  to  the  fullest  extent,  it  is  previously  ground 
with  the  addition  of  water,  and  added  to  the  dye-vessel  in 
the  form  of  a  fine  smooth  paste.  The  "  vat  77  or  dye-vessel 
in  which  the  reduction  of  the  Indigo  and  the  dyeing 
takes  place  is  a  large  tank,  generally  made  of  cast-iron 
(about  2  m.  =  6  ft.  6  in.  wide  and  2  m.  =6  ft.  6  in. 
deep).  For  dyeing  unspun  wool  it  is  generally  round;  for 
piece-dyeing,  square.  The  whole  is  enclosed  in  brickwork, 
so  arranged  that  the  upper  portion  of  the  vat  is  sur- 
rounded by  a  chamber  or  canal,  into  which  steam  can  be 
admitted.  By  this  means  the  liquid  of  the  vat  is  heated 
from  the  outside,  and  a  regular  temperature  can  always  be 
maintained,  without  danger  of  disturbing  the  sediment. 

During  the  "  setting  77  of  the  vat  the  contents  are 
stirred  up,  either  by  hand,  by  means  of  a  rake,  or  by  a 
mechanical  arrangement  fixed  in  the  bottom  of  the  vat, 
and  driven  by  machinery.  Before  dyeing,  the  contents 
are  allowed  to  settle,  since  the  textile  material  must 
always  be  dyed  in  the  clear  liquid.  The  disturbing  of 
the  sediment  is  prevented  as  much  as  possible  by  sus- 
pending in  the  vat,  1  m.  =39  in.  below  the  surface,  a 
so-called  "  trammel,77  i.e.  an  iron  ring  or  frame,  across 
which  coarse  rope  network  is  stretched. 

Fig.  3  gives  the  section  of  a  well-arranged  round 
indigo-vat  for  wool  dyeing,  with  mechanical  stirrer,  etc. 
A  is  the  steam-chamber  surrounding  the  vat,  b  the  steam- 
pipe  for  heating  it,  J  the  trammel-net,  i  the  emptying- 
pipe;  d  is  a  fixed  bar  supporting  the  stirring-screw  o 
and  the  cone  E.  The  parts  drawn  in  dotted  lines  repre- 
sent the  movable  portions  of  the  stirring  arrangement ; 
G  is  a  strong  wooden  bar  which  can  be  readily  fixed  across 
the  top  of  the  vat;  it  supports  a  pair  of  cog-wheels,  and 
the  fast  and  loose  pulleys  H ;  F  is  a  vertical  connecting 
shaft,  which,  by  reason  of  the  guiding  cone  e,  can  be 
readily  connected  with  the  screw  c.    A  cheaper  but  less 

B 


18    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


substantial  arrangement  is  that  in  which  the  vat  is  made 
of  wood,  and  heated  internally  by  a  copper  steam-pipe 
forming  a  spiral  half-way  up  the  walls  of  the  vat.  When 
not  in  use  for  dyeing,  and  to  prevent  loss  of  heat  and 
oxidation  of  the  reduced  indigo,  the  vat  is  covered  with 
a  wooden  lid,  which  is  divided  into  two  or  three  pieces, 
for  the  sake  of  convenient  handling.  It  is  often  the  cus- 
tom to  throw  over  it  a  woollen  cloth  cover  in  addition. 
According  to  the  materials  used  in  preparing  or  "  setting  " 


23 


Fig.  3. — Indigo  Vat. 


a  vat  for  woollen  dyeing,  the  following  vats  may  be  distin- 
guished :  Woad,  potash,  soda,  urine,  and  hydrosulphite. 

Woad  Vat.— In  setting  this  vat  the  following  substances 
are  employed  for  a  vessel  of  the  dimensions  already  given  : 


15 

kilos. 

rrr           £3-0  lb. 

Woad 

.  300 

5) 

==      6G1-3  „ 

10 

5) 

=     22-0  „ 

Madder 

.  2-15 

=  4-4-33-0  „ 

Dry  slaked  lime 

.  12 

>) 

=       26-4  „ 

The  vat  is  first  partly  filled  with  water,  the  crushed 
woad  is  then  added,  and  the  whole  is  well  stirred  up  and 


INDIGO  COLOURING  MATTERS. 


19 


heated  to  about  50°-60°  C.  This  temperature  is  main- 
tained for  24-30  hours,  the  stirring  being  repeated  at  in- 
tervals during  the  first  2  hours.  The  well-ground  In- 
digo, also,  the  bran,  madder,  and  about  half  the  total 
quantity  of  lime,  are  now  added ;  after  well  raking  up  the 
whole  mixture,  the  vat  is  covered  over,  and  left  to  itself 
for  12-24  hours. 

By  this  time  fermentation  has  generally  well  begun. 
It  is  recognised  by  the  following  appearances  :  The  sur- 
face of  the  vat-liquor  becomes  covered  with  a  coppery- 
blue  scum  or  "  flurry.77  On  gently  stirring  the  liquor,  it 
is  seen  to  possess  a  greenish-yellow  colour,  interspersed 
with  blue  veins  or  streaks  of  regenerated  Indigo,  and 
the  general  odour  of  the  vat  is  agreeable.  If  the  bottom 
of  the  vat-liquor  is  disturbed,  a  slight  froth  appears  on 
the  surface,  and  on  bringing  up  a  portion  of  the  sediment 
with  the  rake,  it  shows  evidences  of  being  in  a  state  of 
slight  fermentation,  and  smells  somewhat  sour.  A  piece 
of  wool  immersed  in  the  liquid  for  a  short  time,  and 
then  exposed  to  the  air,  becomes  dyed  blue.  All  these 
appearances  denote  that  the  fermentation  is  progressing 
satisfactorily,  and  it  now  only  becomes  necessary  to  keep 
it  steady  and  under  control,  by  maintaining  the  tempera- 
ture at  45°-50°  C,  adding,  every  two  or  three  hours,  a 
portion  (one-eighth  to  one-fourth)  of  the  remaining  quan- 
tity of  lime,  and  vigorously  stirring  the  whole  contents 
of  the  vat  after  each  addition.  In  the  course  of  the  next 
12-24  hours,  provided  the  fermentation  continues  to  pro- 
gress favourably,  the  vat  is  ready  to  be  used  for  dyeing. 
Excessive  fermentation  is  prevented  by  well-timed  and 
suitable  additions  of  lime;  sluggish  fermentation,  on  the 
contrary,  is  accelerated  by  making  further  additions  of 
bran.  The  dyeing  power  of  the  vat  is  maintained  by  add- 
ing, after  each  day's  work,  fresh  quantities  of  lime  and 
bran,  and  every  other  day  5-8  kg.  ==  11*0-17*6  lb.  Indigo: 
care  being  taken  to  keep  the  temperature  of  the  liquor  at 
about  50°  C.  After  three  or  four  months,  or  whenever 
^he  vat  sediment  becomes  so  bulky  that  there  is  a  difficulty 
in  obtaining  the  clear-liquor  space  necessary  for  good 
dyeing,  no  further  additions  of  Indigo  are  made;  the 
vat  is  then  used  for  dyeing  light  blues,  and  when  its 
colouring  pow^r  is  exhausted,   the  whole  contents  arc 


20    COLOURING  MATTERS  FOR  DYEING  TEXTILES 


thrown  away.  The  woad  vat  gives  rich  and  brilliant 
colours,  and  serves  equally  well  for  light  and  dark  shades 
of  blue.  It  is  the  vat  most  largely  employed  in  Yorkshire 
for  woollen  dyeing. 

Potash  Vat. — This  vat  is  made  up  as  follows: — 

Indigo      ....  10  kilos.  =  -      22*0  lb. 

Madder     ....  2-5     „     ==  4-4-11-0  „ 

Bran         ....  2-5     „     ==  4 -4- 11*0  „ 

Carbonate  of  potash         .  10-15     „     =  22-0-33-0  „ 

The  bran  and  madder  are  first  heated  to  80°~100°  C.  for 
3-4  hours  with  water,  after  which  the  potash  is  added 
*  and  dissolved,  and  the  liquor  is  allowed  to  cool  down  to 
about  40°  C.  The  ground  Indigo  is  then  added,  the  whole 
is  well  stirred,  and  left  for  a  period  of  48  hours  to  ferment, 
an  occasional  stirring  every  12  hours  or  so  being  needed. 

The  appearances  of  a  healthy  state  of  fermentation  in 
the  potash  vat  are  similar  to  those  observed  in  the  woad 
vat. 

This  vat,  owing  to  the  absence  of  such  a  highly  nitro- 
genous substance  as  woad,  is  less  liable  than  the  woad  vat 
to  get  out  of  order,  and  is  altogether  more  easily  managed. 
It  also  dyes  more  rapidly  than  the  woad  vat,  gives 
deeper  but  duller  shades  of  blue,  and  the  colour  does  not 
come  off  so  much  on  milling  with  soap  and  weak  alkalis. 
It  is  best  adapted  for  very  dark  shades  of  navy  blue.  If 
unspun  wool  is  dyed  in  this  vat,  care  must  be  taken  to  wash 
it  thoroughly  in  water  afterwards,  otherwise  it  is  apt 
to  spin  badly. 

Soda  Vat  (German  Vat). — This  vat  is  set  with  the  fol- 
lowing materials  :  Indigo,  10  kg.  =  22*0  lb.  ;  bran,  60-100 
kg.  =  132  2-220*4  lb.  (or  10-15  kg.  =  22'0-33'0  lb.  of  treacle 
instead) ;  carbonate  of  soda  crystals,  20  kg.  =  44  0  lb.  ; 
slaked  lime,  5  kg.  =  1T0  lb. 

The  bran  is  first  boiled  with  the  water  for  2-3  hours, 
the  liquid  is  then  cooled  down  to  40°-50°  C,  the  remaining 
ingredients  are  added,  and  the  whole  is  wrell  stirred  up 
and  left  to  ferment  for  2-3  days,  with  only  an  occasional 
stirring.  During  the  progress  of  the  fermentation,  lime 
and  soda,  as  occasion  requires,  are  added  from  time  to 
time.  After  being  used  for  dyeing,  the  vat  is  replenished 
with  Indigo,  soda,  and  lime.    This  vat  is  cheaper  than  the 


INDIGO  COLOURING  MATTERS. 


21 


potash  vat,  because  of  the  difference  in  price  between 
potash  and  soda;  it  also  lasts  longer.  It  is,  however,  more 
liable  to  get  out  of  order,  though  always  more  easily 
managed  than  the  woad  vat. 

Urine  Vat. — This  vat,  although  of  minor  importance, 
is  suitable  for  working  on  a  small  scale.  It  is  used  by 
those  who  only  require  to  dye  vat-indigo  blues  occasion- 
ally, or  in  comparatively  small  quantities.  The  vat  is 
made  up  as  follows  :  Stale  urine,  500  litres  =  110  gals. ; 
common  salt,  3-4  kg.  =  6  6-8*8  lb.  Heat  the  mixture 
to  50°-60°  C.  for  4-5  hours,  with  frequent  stirring ;  then 
add  1  kg.  of  madder  and  1  kg.  of  ground  Indigo,  stir  well, 
and  allow  to  ferment  till  the  Indigo  is  reduced.  In  this 
vat  the  indigo-white  dissolves  in  the  ammonium  carbonate 
arising  from  the  decomposition  of  the  urea  contained 
in  the  urine. 

Hydrosiilphite  Vat. — The  active  reducing  agent  in  this 
vat  is  a  solution  of  hyposulphurous  (hydrosulphurous) 
acid,  which  may  be  produced  by  the  action  of  zinc  upon 
a  solution  of  sulphurous  acid,  according  to  the  following 
equation  : — 

H2S03  +  Zn  =  H2S02  +  ZnO. 

Sulphurous       Zinc.     Hyposulphur-    Zinc  oxide, 
acid.  ousacid. 

In  practice  the  zinc  is  allowed  to  act  upon  a  concen- 
trated solution  of  sodium  hydrogen  sulphite  (bisulphite), 
instead  of  sulphurous  acid,  in  which  case  the  reaction  is 
somewhat  more  complicated,  there  being  produced  a  solu- 
tion of  sodium  hydrogen  hyposulphite  and  zinc  sodium 
sulphite  which  separates  out,  thus  : 

Zn  +  3NaHS03  -  NaHS02  +  ZnNa2(S03)2  +  ILO. 

Sodium  hydro-       Sodium  hydro-         Zinc  sodium  sul- 
gen  sulphite.        gen    hyposul-  phitc. 
phite. 

The  reduction  of  the  indigotin  by  means  of  the  acid 
sodium  hyposulphite  may  be  represented  by  the  follow- 
ing equation  : — 

C16H10N2O2  +  NaHS02  +  NaHO  = 

Indigotin.  Acid  sodium 

hyposulphite. 

C]6H12N202- •+  Na2S03; 

Indigo.white.        _  -  Disodium 
sulphite. 


22     COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


It  is  not  customary  to  reduce  the  Indigo  in  each  vat 
separately,  but  rather  to  make  a  very  concentrated  solu- 
tion of  reduced  Indigo,  and  to  use  this  stock  solution  for 
preparing  and  replenishing  the  dye-vats. 

The  setting  of  a  hydrosulphite  vat  naturally  divides 
itself  into  three  phases  : — 

1.  The  formation  of  acid  hyposulphite  of  soda  accord- 
ing to  the  above  equation. 

2.  The  changing  of  this  acid  hyposulphite  into  neutral 
hyposulphite  by  mixing  it  with  lime. 


Fig.  i. — Apparatus  for  Preparing  Hydrosulphite  Vat  Liquor. 

3.  The  mixing  of  this  solution  with  Indigo  and  a 
further  quantity  of  lime,  in  order  to  produce  the  stock 
solution  of  reduced  Indigo.  Fig.  4  shows  a  suitable  ap- 
paratus in  which  to  conduct  the  first  two  operations. 

(1.)  A  vessel  a,  provided  with  an  agitator,  and  which 
can  be  hermetically  closed,  is  packed  full  of  small  rolls 
of  zinc-foil,  then  filled  up  with  bisulphite  of  soda,  55°  Tw. 
(Sp.  Gr.  1'275),  and  thoroughly  saturated  with  sulphurous 
acid.  The  size  of  the  vessel  should  be  just  adapted  to 
the  quantity  of  hyposulphite  required  for  immediate  use. 


INDIGO  COLOURING  MATTERS. 


23 


and  so  that  it  may  be  entirely  full  of  zinc,  in  order  to 
prevent  oxidation  as  much  as  possible.  The  zinc  and 
bisulphite  of  soda  are  allowed  to  act  upon  each  other, 
with  occasional  stirring,  for  about  an  hour  at  least.  The 
sodium  hydrogen  hyposulphite  thus  produced  stands  at 
62°  Tw.  (Sp.  Gr.  l'3l),  and,  since  it  is  very  unstable,  it 
must  be  used  at  once,  either  for  reducing  Indigo  or  for 
making  the  neutral  sodium  hyposulphite.  One  litre  = 
1  quart  bisulphite  of  soda,  55°  Tw.  (Sp.  Gr.  1275)  requires 
100-125  g.  of  zinc,  of  which  quantity  about  50  g-  = 
1'6  oz.  dissolve  during  the  operation.  Granulated  zinc 
or  zinc  powder  may  be  used  instead  of  zinc-foil,  but  the 
former  retains  much  of  the  liquid  when  the  vessel  is 
emptied,  and  cannot  be  so  readily  washed.  The  latter 
is  perhaps  the  best  form  of  zinc  to  use,  but  it  varies  con- 
siderably in  composition,  and  owing  to  its  being  in  the 
state  of  such  a  fine  powder,  the  liquid  heats  considerably 
during  the  mixing,  so  that  there  is  always  the  danger  of 
a  portion  of  the  hyposulphite  being  decomposed.  When- 
ever the  acid  hyposulphite  of  soda  has  been  drawn  off, 
the  zinc  should  be  rinsed  with  water,  and,  if  not  im- 
mediately required  again,  the  vessel  should  be  filled  up 
with  water,  in  order  to  prevent,  as  much  as  possible,  the 
oxidation  of  the  zinc. 

When  a  fresh  quantity  of  hyposulphite  is  to  be  made 
this  water  is  drawn  off  and  the  zinc  is  rinsed,  first, 
with  water  slightly  acidulated  with  hydrochloric  acid, 
and  afterwards  with  water.  The  small  quantity  of  zinc 
dissolved  in  the  previous  operation  is  replaced  by  an 
addition  of  fresh  zinc-foil,  so  that  the  vessel  may  be 
entirely  full.  Bisulphite  of  soda  solution  is  then  poured 
over  it,  and  the  process  as  already  described  is  repeated. 

(2.)  In  order  to  change  the  unstable  acid  sodium  hypo- 
sulphite thus  produced  into  the  more  stable  neutral  hypo- 
sulphite, it  is  drawn  off  into  another  closed  vessel  B, 
and  there  mixed  with  milk  of  lime,  which  precipitates 
zinc  oxide  and  calcium  sulphite.  One  litre  —  1  quart  of 
acid  sodium  hyposulphite,  62°  Tw.  (Sp.  Gr.  1*31)  requires 
about  460  g.  =  14'7  oz.  of  milk  of  lime,  containing  200  g. 
=5=  6*4  oz.  of  quicklime  per  litre  =  1  quart.  The  mixture 
is  well  agitated,  and,  after  settling,  the  clear  liquid  is 
drawn  off.    A  better  yield  is  obtained  by  passing  the 


24    COLOURING  MATTERS  FOR  DYEING  TEXTILES, 


mixture  through  a  filter-press.  The  weight  of  neutral 
hyposulphite  thus  obtained  is  about  the  same  as  that  of 
the  original  sodium  bisulphite,  and  it  has  a  density  of 
about  36°  Tw.  (Sp.  Gr.  112).  It  is  best  to  employ  the 
solution  as  soon  as  possible  for  reducing  Indigo,  and  not 
to  make  more  than  is  required  for  immediate  use.  If  it 
is  ever  found  necessary  to  keep  it  for  some  time,  it  must 
be  made  alkaline  by  adding  a  little  lime,  but  this  should 
only  be  done  as  an  exception  and  not  become  general. 

(3.)  The  stock  solution  of  reduced  Indigo  is  made  by 
heating  to  a  temperature  of  70°-75°  C.  the  following  mix- 
ture :  Indigo,  1  kg.  =  2  2  lb.  ;  milk  of  lime  (containing 
200  g.  6'4  oz.  of  quicklime  per  litre  =  1  quart  of 
water),  1-1*3  kg.  —  2'2-3  lb.  ;  and  so  much  neutral  hypo- 
sulphite, 36°  Tw.  (Sp.  Gr.  1'18),  as  is  obtained  from 
8-10  kg.  =  17*6-22  0  lb.  of  concentrated  sodium  bisulphite. 
The  Indigo  is  rapidly  and  completely  reduced,  and  a  com- 
paratively clear  greenish-yellow  solution  is  obtained,  con- 
taining about  1  kg.  of  Indigo  per  10-15  litres  =  2*-3'3  gals, 
of  solution.  With  an  insufficiency  of  lime,  part  of  the 
indigo-white  is  not  dissolved,  but  remains  as  a  dense 
white  precipitate.  In  setting  a  hydrosulphite  vat,  the 
vat  is  first  filled  with  water  heated  to  50°  C.  ;  it  is  then 
deprived  of  the  oxygen  it  naturally  contained,  by  adding  a 
little  of  the  neutral  hyposulphite.  The  concentrated 
stock  solution  of  reduced  Indigo  is  then  added  in  suffi- 
cient quantity  to  make  a  vat  of  the  required  strength, 
and  since  there  is  no  sediment,  the  dyeing  may  be  at  once 
proceeded  with.  The  dyeing  power  is  maintained  by 
adding  fresh  quantities  of  the  concentrated  solution  of 
reduced  Indigo.  The  liquid  of  the  vat  should  always 
contain  an  excess  of  hyposulphite.  It  should  have  a 
yellow  colour,  and  be  clear. 

If  from  any  cause  excessive  oxidation  of  the  indigo- 
white  takes  place,  and  the  liquor  becomes  greenish,  a  little 
more  hyposulphite,  and  possibly  also  milk  of  lime,  must  be 
added,  and  the  whole  heated  to  70°-75°  C.,  in  order  to 
accelerate  the  reduction  of  the  Indigo  and  restore  the 
normal  yellow  colour.  When  the  vat  is  in  use  the  alka- 
linity of  the  liquid  increases,  and  there  is  a  danger  of 
both  the  colour  and  the  fibre  being  injured;  hence  it  is 
advisable  to  partially  neutralise  the  excess  of  alkali  from 


INDIGO  COLOURING  MATTERS. 


25 


time  to  time,  by  making  slight  additions  of  dilute  hydro- 
chloric acid. 

Defects  in  Indigo  Vats.—  All  the  fermentation  vats  are 
subject  to  derangements,  by  which  they  become  more  or  less 
useless.  The  most  serious  defect  is  produced  by  using  a 
deficiency  of  lime,  in  which  case  the  fermentation  becomes 
more  and  more  active;  if  allowed  to  proceed  too  far,  the 
Indigo  is  totally  and  irretrievably  destroyed. 

This  defect  is  recognised  by  the  following  characteris- 
tics :  The  flurry  disappears,  the  vat  liquor  has  a  muddy 
appearance,  and  gives  off  a  very  disagreeable  odour;  it 
has  a  dirty  reddish-yellow  tint,  and  acquires  the  property 
of  gradually  destroying  the  colour  of  a  small  piece  of 
indigo-blue  cloth  which  may  be  plunged  into  it. 

The  only  remedy  to  be  applied,  in  such  a  case,  is  to 
heat  the  vat  liquor  to  90°  C,  and  add  lime  or  potash,  etc., 
according  to  the  kind  of  vat.  If  this  has  not  the  effect 
of  arresting  the  fermentation,  the  vat  will  "  run  away," 
or  be  "  lost,"  as  the  dyers  term  it.  The  woad  vat  is  the 
one  most  liable  to  this  defect,  because  it  contains  a  very 
large  quantity  of  nitrogenous  matter. 

Another  defect  is  caused  by  dyeing  too  many  pieces  in 
rapid  succession.  Under  these  circumstances  the  appear- 
ance of  the  vat  becomes  very  similar  to  that  exhibited 
in  the  last  defect,  but  the  odour  is  faintly  ammoniacal. 
A  vat  in  this  state  gives  much  paler  colours  than  when 
it  is  in  its  normal  condition.  To  remedy  this  defect,  it  is 
advisable,  first,  to  add  a  little  lime — perchance  one  might 
have  been  deceived  by  the  colour  of  the  vat— and,  after 
some  time,  to  add  a  little  woad  and  warm  the  vat,  en- 
deavouring thus  to  promote  rapid  reduction  of  the  pre- 
cipitated Indigo,  and  to  get  rid  of  the  excessive  amount 
of  oxygen  which  has  been  introduced  into  the  vat.  A 
quicker  method  is  to  add  a  small  quantity  of  ferrous  sul- 
phate, and  then  to  stir  up  the  liquor  thoroughly. 

A  third  defect  is  caused  by  the  presence  in  the  vat  of 
such  an  excess  of  lime  as  to  precipitate  the  indigo-white. 
In  this  case,  the  vat  liquor  becomes  of  a  dark  brown 
colour,  and  the  healthy  odour  and  the  blue  scum  or 
"  flurry  "  disappear.  When  noticed  in  time,  this  defect 
is  remedied  by  adding  at  intervals  a  small  quantity 
(say  §  kg.  =1  lb.)  of  ferrous  sulphate,  or  of  dilute  sul- 


26    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


phuric  acid,  and  stirring  up  the  vat.  This  addition  pre- 
cipitates the  excess  of  lime  as  calcium  sulphate. 

Dyeing  with  the  Indigo  Vat. — The  operations  involved 
in  setting,  working,  and  keeping  the  fermentation  indigo- 
vats  in  order  are  very  simple,  but  since  the  phenomena 
of  fermentation  are  for  the  most  part  extremely  complex 
and  ill-understood,  long-continued  and  close  observation 
is  necessary  before  one  is  able  at  a  glance  to  recognise 
the  features  characteristic  of  the  very  various  conditions 
which  the  vat  liquid  may  assume. 

Woollen  material,  of  whatever  kind,  must  always  be 
well  boiled  with  water,  and  then  at  once  passed  into  tepid 
water  and  squeezed  before  it  is  entered  into  the  indigo- 
vat.  It  should  never  be  allowed  to  lie  in  irregular  heaps 
after  boiling,  since  this  causes  unequal  dyeing.  This 
wetting-out  process  not  only  accelerates  the  absorption  of 
the  vat  liquor  by  the  material,  but  also  produces  more 
even  dyeing,  and  prevents  the  introduction  into  the  vat 
of  a  large  amount  of  air,  which  would  oxidise  the  indigo- 
white,  and  cause  a  precipitate  of  indigo-blue  merely  to 
adhere  mechanically  and  loosely  to  the  surface  of  the 
material.  Cloth  previously  milled  with  soap  should  be 
well  boiled  with  water  and  washed,  in  order  to  remove  all 
traces  of  soap,  otherwise  "  cloudy  "  or  irregular  dyeing 
will  result,  through  the  precipitation  on  the  cloth  of 
a  lime-soap,  which,  being  of  a  sticky  nature,  acts  as  a 
resist.  Before  beginning  to  dye,  the  blue  scum  on  the 
surface  of  the  vat  liquor  must  always  be  skimmed  off, 
in  order  to  prevent  it  from  producing  irregular  spots 
on  the  material,  especially  in  the  case  of  cloth-dyeing. 

Loose  wool  is  gently  moved  about,  by  means  of  poles, 
in  that  portion  of  the  vat  liquor  which  is  above  the  tram- 
mel-net, care  being  taken  at  this  stage  never  to  bring  it 
above  the  surface  and  thus  expose  it  to  the  air.  Loose 
wool  is  best  dyed  in  a  vat  in  which  the  fermentation  is 
slightly  active.  When  it  has  been  immersed,  and  worked 
the  length  of  time  necessary  to  obtain  the  intensity  of 
colour  required  (say  ten  minutes  to  two  hours),  it  is 
taken  out,  placed  in  strong  bags  of  netted  cord,  and  the 
excess  of  liquor  is  well  wrung  out.  The  wool  is  then 
thrown  into  heaps,  and  remains  exposed  to  the  air  until 
the  blue  colour  is  fully  developed.    The  dyed  wool  must 


INDIGO  COLOURING  MATTERS. 


27 


now  be  well  washed  with  water  slightly  acidulated  witL 
sulphuric  or  hydrochloric  acid,  in  order  to  remove  loosely 
adhering  Indigo  and  all  soluble  material  absorbed  from 
the  vat,  also  to  dissolve  away  any  adhering  lime  carbonate. 
This  treatment  prevents  the  greyish  appearance  the  blue 
would  otherwise  acquire  on  drying,  and  gives  it  greater 
brilliancy.  The  acid  must,  of  course,  be  entirely  removed 
by  a  final  washing  in  water  before  drying. 

In  dyeing  woollen  yarn  each  hank  is  worked  in  the 
vat  separately  for  a  short  time,  and  at  once  wrung  out 
and  thrown  on  the  floor  to  oxidise.  To  obtain  dark  shades 
the  whole  process  must  be  repeated  several  times.  The 
subsequent  operations  of  washing,  etc.,  are  the  same  as  in 
the  case  of  dyeing  loose  wool. 

Woollen  cloth,  after  boiling  and  cooling  as  already 
mentioned,  is  dyed  by  moving  it  about,  or  "  hawking  " 
it,  in  the  vat  liquid  above  the  trammel-net,  by  means  of 
an  instrument  called  a  "  hawk/'  a  double  hook,  one  of 
which  is  held  in  each  hand  by  the  workman.  Care  must 
be  taken  during  the  whole  operation  not  to  raise  the 
cloth  above  the  surface  of  the  liquid,  in  order  to  avoid 
irregular  oxidation,  and,  consequently,  uneven  dyeing. 
The  duration  of  the  hawking  process  may  vary  from 
twenty  minutes  to  two  hours,  according  to  the  dyeing 
power  or  strength  of  the  vat,  the  texture  of  the  cloth,  and 
the  depth  of  colour  required.  Since  the  vat  solution  is 
not  so  readily  and  thoroughly  absorbed  by  thick  and 
closely  woven  cloth,  such  material  requires  longer  time 
than  if  it  were  thin  and  loosely  woven.  In  many  well- 
ordered  dye-houses  the  moving  about  of  the  cloth  in  the 
vat  liquor  is  effected  by  a  so-called  hawking  machine. 
This  consists  essentially  of  a  framework,  supporting  a 
pair  of  squeezing  rollers  a  little  below  the  surface  of  the 
vat  liquor.  The  cloth  to  be  dyed  is  opened  out,  and  the 
ends  are  stitched  together,  so  as  to  form  a  broad,  endless 
band;  this  is  continually  drawn  through  the  vat  liquor 
and  between  the  squeezing  rollers  until  the  shade  required 
is  obtained;  the  squeezing  rollers  are  provided  with 
close-fitting  iron  scrapers,  which  prevent  the  cloth  from 
wrapping  round  them,  and  the  framework  has  guiding 
pegs  to  keep  the  cloth  from  running  to  one  side.  The 
squeezing  rollers  are  turned  either  by  hand  or  steam- 


28    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


power.  Such  machines  give  much  more  regular  work,  and 
in  thick  cloth  the  dye  may  be  made  to  penetrate  more 
thoroughly  to  the  centre  of  the  fabric,  it  being  possible 
to  regulate  at  will  the  pressure  of  the  squeezing  rollers. 

In  order  to  dye  to  an  exact  shade  of  dark  blue,  the 
cloth  is  worked  in  a  strong  vat  until  a  blue  a  little 
lighter  in  shade  than  that  ultimately  required  is  obtained ; 
it  is  then  withdrawn  from  the  vat,  and  the  colour  is  fully 
developed  by  exposure  to  the  air,  after  which  the  opera- 
tions are  repeated  in  a  weaker  vat  till  the  desired  shade 
is  gained.  If  a  light  shade  of  blue  is  wanted,  the  cloth 
is  at  once  worked  in  a  weak  vat  for  the  requisite  length  of 
time.  Cloth  dyes  best  in  a  vat  in  which  the  fermenta- 
tion is  kept  very  moderate.  After  dyeing,  the  cloth 
must  be  rinsed  in  acidulated  water,  and  well  washed, 
as  already  mentioned  in  the  case  of  loose  wool.  In  order 
to  remove  every  trace  of  loosely  adhering  Indigo,  a  good 
milling  with  soap  and  fuller's  earth  is  eventually  given, 
so  that  the  finished  piece  will  not  soil  a  white  handker- 
chief when  rubbed  on  its  surface.  Previ'ous  to  fulling  it 
is  well  to  boil  the  goods'  with  a  solution  of  alum  or  bichro- 
mate of  potash  and  tartaric  acid.  This  operation  makes 
the  colour  much  faster  against  light  and  rubbing.  As 
a  rule,  the  loose  Indigo  removed  during  the  fulling  opera- 
tion is  allowed  to  run  to  waste,  but  it  is  probable  that 
much  of  it  might  be  profitably  regained  from  the  sedi- 
ment of  the  fulling  mills  by  a  system  of  washing  based 
on  the  difference  of  specific  gravity  between  the  fuller's 
earth  and  indigotin ;  or  one  might  mix  the  sediment  with 
ferrous  sulphate  solution,  let  settle,  draw  off  the  clear 
solution  of  reduced  Indigo,  oxidise  it,  and  collect  the 
regenerated  and  precipitated  Indigo. 

By  boiling  the  cloth  (after  dyeing  and  washing)  with 
Barwood,  Sanderswood,  or  Camwood,  the  blue  is  said  to 
be  better  fixed  and  faster  against  light  than  without 
this  treatment.  It  is  not  so  liable  to  bleach  at  the  cut 
edges,  etc.  Steaming  the  goods  for  half  an  hour  makes 
the  blue  a  little  more  violet,  but  faster  against  light. 
Vat-blues,  which  have  been  boiled  with  alum  and  tartar 
after  dyeing,  become  slightly  paler  by  the  operation,  but 
are  rendered  much,  more  stable  against  light;  the 
ultimate  gain  being  much  greater  than  the  primary  loss, 


indigo  colouring  matters. 


2U 


Exposure  to  light  gives  vat-blue  a  violet  tint.  By  boiling 
with  alum  and  tartar,  after  dyeing  and  washing,  etc., 
and  steaming  half  an  hour  in  addition,  the  colour  is 
only  slightly  weaker,  and  the  greatest  fastness  against 
light  is  obtained.  If  treated  in  this  way,  the  colour  be- 
comes darker  during  the  first  five  months  of  exposure  to 
light  and  air,  and  at  the  end  of  the  year  possesses  the  same 
depth  of  shade  as  at  first.  From  these  facts  it  may  be  in- 
ferred that  in  the  case  of  woaded  browns,  greens,  etc., 
the  dyeing  in  the  woad-vat  should  precede  the  mordanting 
and  dyeing  of  the  added  colours. 

Silk  is  now  seldom  dyed  vat-blue.  Lime  tends  to 
make  the  silk  harsh  and  brittle,  hence  it  is  well  to  employ 
the  soda  or  potash  vat,  the  hydrosulphite  vat,  or,  better 
still,  a  vat  in  which  the  Indigo  is  reduced  by  zinc  powder 
and  ammonia. 

Indigo  Extract;  Indigo  Carmine  [C1GH8N202(HS03)2]. 
— This  colouring  matter  is  the  product  of  the  action  of 
strong  sulphuric  acid  on  Indigo. 

Indigo  Extract  has  no  affinity  for  cotton,  and  cannot 
be  used  by  the  cotton  dyer.  It  is,  however,  occasionally 
used  by  bleachers  for  tinting. 

Application  of  Indigo  Extract  to  Wool. — The  blue  ob- 
tained on  wool  by  means  of  Indigo  Extract  and  Indigo 
Carmine  is  sometimes  called  "  Saxony  blue."  It  is  a  much 
brighter  colour  than  that  obtained  by  means  of  the  indigo- 
vat,  but  is  very  far  from  being  so  fast  either  to  light  or 
to  the  action  of  soap  and  weak  alkalis.  Hence  it  does 
not  stand  milling  well.  Wool  must  always  be  dyed  with 
the  above-mentioned  colouring  matters  in  an  acid  bath. 
When  "  sour  extract  ;?  (i.e.  indigotin-disulphonic  acid, 
containing  free  sulphuric  acid)  is  used,  no  other  addition 
to  the  dye-bath  than  the  extract  itself  is  necessary.  The 
wool  may  be  entered  at  40°-50°  C.  ;  the  temperature  of  the 
bath  should  then  be  gradually  raised  in  the  course  of  half 
an  hour  to  the  boiling  point,  the  dyeing  continued  for 
half  an  hour  longer.  By  dyeing  at  70°-80°  C.  a  purer  blue 
is  obtained,  but  the  colour  is  apt  to  have  an  uneven, 
speckled  appearance.  Boiling  levels  the  colour,  but  makes 
the  shade  greener.  When  Indigo  Carmine  is  employed, 
this  being  the  sodium  salt  of  indigotin-disulphonic  acid, 
it  is  necessary  to  add  to  the  dye-bath,  along  with  the 


30    COLOURING  MATTE  US  FOB  DYEING  TEXTILES 


colouring  matter,  5-10  %  of  sulphuric  acid,  168°  Tw.,  so 
that  this  may  combine  with  the  sodium  and  liberate  the 
colour-acid  itself.  Without  this  addition  the  full  colour- 
ing power  of  the  Indigo  Carmine  would  not  be  de- 
veloped. The  addition  of  10-20  %  of  sodium  sulphato 
to  the  dye-bath  along  with  sulphuric  acid  tends  to 
make  the  colour  uniform  or  level.  Sometimes  alum  is 
also  added  to  the  bath  in  order  to  mordant  the  wool 
slightly,  and  permit  the  application  of  Logwood  and  other 
polygenetic  colouring  matters. 

Application  of  Indigo  Extract  to  Silk. — Dye  at  a  tem- 
perature of  40°-50°  C.  in  a  bath  acidified  with  sulphuric 
acid  and  containing  the  amount  of  Indigo  Carmine  solu- 
tion necessary  to  produce  the  depth  of  shade  required. 

Another  method  is  to  mordant  the  silk  first  with 
alum  by  steeping  twelve  hours  in  a  solution  of  25  % 
of  alum,  and  then,  without  washing,  to  dye  in  a  solution 
of  Indigo  Carmine  with  the  addition  of  about  10  %  of 
alum  to  the  dye-bath.  If  scroop  is  required,  a  further 
addition  of  a  little  acetic  acid  or  cream  of  tartar  is 
necessary. 

In  this  case  the  alum  acts  in  no  sense  as  a  mordant 
for  the  Indigo  Carmine,  but  makes  it  possible  to  redden 
the  shade,  or  even  to  produce  a  violet  colour,  by  adding 
Cochineal  decoction  to  the  dye-bath ;  by  the  further  addi- 
tion of  decoctions  of  Old  Fustic,  Logwood,  Orchil,  etc., 
various  shades— grey,  drab,  brown,  etc. — may  be  obtained, 
according  to  the  amount  of  each  colouring  matter  em- 
ployed. 

By  adding  to  the  dye-bath  a  decoction  of  10-20  %  of 
Logwood  a  dark  shade  of  blue  is  obtained;  the  addition 
of  too  much  Logwood  decoction,  however,  must  be  avoided, 
otherwise  the  colour  is  apt  to  become  dull.  The  most 
rational  method  of  adding  the  colour  yielded  by  Log- 
wood to  that  of  the  Indigo  Carmine  is  to  dye  with  the  two 
colouring  matters  in  separate  baths. 


CHAPTER  II. 


LOGWOOD  COLOURING  MATTERS. 

Logwood. — This  dyewood  is  the  heart  wood  of  Ilcema- 
toxylon  campechianum,  grown  in  Central  America. 

Application  of  Logwood  to  Cotton. — The  principal  use 
of  Logwood  in  cotton-dyeing  is  for  the  production  of 
blacks  and  greys;  it  may,  however,  also  serve  for  purples, 
blues,  and  numerous  composite  colours.  In  conjunction 
with  other  colouring  matters,  it  is  employed  for  the  pro- 
duction of  numerous  compound  shades,  its  use  being,  in 
such  cases,  to  make  the  colour  darker,  or  of  a  bluer  tone. 

Logwood  Blacks. — The  method  of  obtaining  a  logwood 
black  consists  essentially  in  mordanting  the  cotton  with 
a  salt  of  iron,  and  then  dyeing  with  a  decoction  of 
Logwood.  Numerous  modes  of  applying  this  simple  process 
are  in  general  use,  but  the  principle  is  always  the  same. 

In  order  to  mordant  the  cotton,  it  may  be  worked  in 
a  cold  solution  of  pyrolignite  or  nitrate  of  iron,  at  about 
5°  Tw.  (Sp.  Gr.  1-025)  till  thoroughly  saturated;  after 
squeezing,  the  iron  is  fixed  by  working  in  a  cold  weak 
bath  of  sodium  carbonate,  or  milk  of  lime ;  the  cotton 
is  finally  well  washed  in  water. 

Another  method  of  mordanting,  and  one  which  gives 
faster  blacks,  is  to  fix  on  the  fibre  a  tannate  of  iron 
instead  of  ferric  oxide,  as  in  the  last  case.  Work  the 
cotton  in  a  cold  infusion  of  about  30-40  %  of  Sumach,  or 
its  equivalent  of  other  tannin  matter  (ground  Gall-nuts, 
Myrabolams,  etc.),  and  allow  it  to  steep  for  several  hours, 
or  even  over-night;  remove  the  excess,  and,  without  wash- 
ing, work  for  about  half  an  hour  in  a  cold  solution  of 
pyrolignite  or  nitrate  of  iron  at  2°-4~  Tw.  (Sp.  Gr.  l'Ol- 
1*02),  and  wash  well.  In  order  to  remove  all  traces  of 
acid,  and  to  fix  more  completely  on  the  fibre  a  basic  salt 
of  iron,  it  is  advisable  before  washing  to  work  the  cotton 


32    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


in  a  cold  bath  of  chalk-water,  or  in  weak  milk-of-lime. 
Not  unfrequently  a  lime  bath  is  applied  immediately  after 
sumaching  and  before  passing  into  the  iron  bath.  In  this 
case  a  tannate  of  lime  will  be  formed  upon  the  fibre, 
and  the  double  decomposition  with  the  iron  salt  is  facili- 
tated, since  the  lime  at  once  takes  up  the  acid  liberated. 

In  warp  dyeing  the  whole  process  is  continuous,  and 
the  cotton,  after  being  steeped  in  a  decoction  of  myrabo- 
lams,  is  passed  successively  through  baths  containing 
lime-water,  nitrate  of  iron,  logwood  liquor,  dilute  iron 
solution,  and  water. 

For  low-class  goods  many  dyers  substitute  ferrous  sul- 
phate for  the  pyrolignite  and  nitrate  of  iron. 

The  pyrolignite  of  iron  may  also  be  mixed  with  an 
equal  or  somewhat  smaller  amount  of  aluminium  acetate 
(red  liquor)  at  5°  Tw.  (Sp.  Gr.  1*025),  in  which  case  it 
may  be  better  to  fix  the  mordants  by  working  the  cotton 
for  a  quarter  of  an  hour  at  50°-60°  C,  in  a  dilute  solution 
of  phosphate  or  arsenate  of  soda. 

An  aluminium  mordant  alone  would  give  a  dull  lilac 
shade,  but  along  with  an  iron  mordant  it  helps  to  re- 
move the  unpleasant  reddish  or  rusty  appearance  of  the 
blacks  otherwise  obtained. 

When  Catechu  is  the  tannin  matter  employed,  the 
cotton  should  be  worked  in  a  boiling  decoction  of  it,  and 
allowed  to  steep  till  cold,  in  order  to  effect  the  precipita- 
tion on  the  fibre  of  the  maximum  amount  of  catechin.  The 
cotton  may  afterwards  be  worked  5-15  minutes  in  a  boil- 
ing solution  of  bichromate  of  potash  (5  g.  =  017  ozs.  per 
litre  =  1  quart),  before  passing  it  into  the  bath  of  pyro- 
lignite of  iron,  though  this  is  not  absolutely  necessary. 

By  whichever  method  the  mordanting  is  effected,  the 
dyeing  takes  place  in  a  separate  bath  containing  a  suit- 
able amount  of  freshly-made  Logwood  decoction,  together 
with  a  small  quantity  of  extract  of  Old  Fustic,  or  of 
Quercitron  Bark.  If  an  iron  mordant  only  has  been 
employed,  it  is  beneficial  to  add  also  a  small  quantity 
of  copper  sulphate  to  the  dye-bath,  in  order  to  prevent 
the  cotton  from  acquiring  the  rusty  appearance  already 
referred  to. 

The  cotton  is  introduced  into  the  cold  dye  liquor,  and 
the  temperature  is  gradually  raised  to  the  boiling  point. 


LOGWOOD  COLOURING  MATTERS.  33 


After  dyeing,  the  cotton  may  be  passed  through  a  solu- 
tion of  bichromate  of  potash,  0*5  g.  =  0  017  oz.  per  litre, 
at  60°  C.  This  operation  gives  intensity  and  fastness  to 
the  black,  since  any  excess  of  colouring  matter  is  fixed 
as  a  chromic  oxide  lake. 

The  dyed  cotton  is  washed  and  worked  in  a  solution 
of  soap,  5  g.  =  0*17  oz.  per  litre  (1  quart),  at  a  moderate 
temperature,  then  squeezed  and  dried.  This  final  soaping 
removes  any  bronze  appearance,  and  imparts  to  the  colour 
a  bluer  and  more  agreeable  tone.  The  cotton  also  ac- 
quires a  softer  feel. 

The  following  is  a  method  by  which  a  chrome  black 
on  cotton  can  be  obtained  in  a  single  bath  : 

Dissolve  1*5  kg.  =  3*3  lb.  of  bichromate  of  potash  in 
a  small  quantity  of  water,  mix  the  solution  with  500  litres 
=  HO'O  gals,  of  Logwood  decoction  at  3°  Tw.  (Sp.  Gr. 
1015),  and  add  3  5  kg.  =  7*7  lb.  of  hydrochloric  acid,  34° 
Tw.  (Sp.  Gr.  1*17).  The  cotton  is  introduced  into  the 
cold  solution,  and  the  temperature  is  very  gradually 
raised  to  the  boiling  point.  The  cotton  acquires  at  first 
a  deep  indigo-blue  shade,  which  changes  to  a  blue-black 
on  washing  with  a  calcareous  water. 

A  slight  modification  of  this  process  which  may  be 
adopted  is  to  work  the  cotton  in  a  solution  containing 
at  first  only  the  bichromate  of  potash  and  hydrochloric 
acid,  and  to  add  the  decoction  of  Logwood  to  the  bath,  in 
small  portions  from  time  to  time,  gradually  raising  the 
temperature  as  before. 

Another  method  of  producing  a  Logwood  black  is  to 
use  a  bath  containing  Logwood  extract  and  copper  acetate, 
entering  the  cotton  cold,  raising  the  temperature  gradu- 
ally to  50°  C,  and  dyeing  at  that  temperature  until  the 
colour  is  sufficiently  developed. 

Copper  sulphate,  to  the  amount  of  about  4  %  of  the 
weight  of  cotton,  is  frequently  used  instead  of  acetate, 
and  an  addition  of  4  %  of  soda-ash  is  made  to  the  bath 
along  with  20  %  of  solid  Logwood  extract. 

The  cotton  is  passed  rapidly  through  this  mixture, 
heated  to  60°-80°  C,  and  then  allowed  to  oxidise  or 
"  smother  "  for  5-6  hours.  This  process  requires  to  be 
repeated  several  times  before  a  full  black  is  obtained. 
The  method  is  not  economical  for  ordinary  use,  but  it  is 
o 


34    COLOURING  MATTERS  FOE  DYEING  TEXTILES. 


said  to  yield  a  black  which  withstands  milling  with  soap 
very  well.  Carbonate  of  copper  may  also  be  applied  in 
the  above  process,  instead  of  copper  sulphate  and  soda- 
ash. 

The  methods  already  given  may  be  adapted  to  the 
dyeing  of  unspun  cotton.  The  following  method  of  dye- 
ing a  chrome  black  is  said  to  be  specially  applicable  to 
such  as  must  withstand  the  operation  of  fulling.  Wet 
out  the  cotton  well  in  boiling  water,  then  boil  in  a  strong 
solution  of  about  30  %  of  solid  Logwood  extract,  drain, 
and  allow  it  to  lie  exposed  to  the  air  for  some  time; 
complete  the  oxidation  thus  begun  by  working  it  one  hour 
in  a  cold  solution  of  8  %  of  bichromate  of  potash  and 
6  %  of  copper  sulphate,  wash  and  complete  the  dyeing  in 
a  bath  containing  10  %  of  Logwood  extract;  enter  the 
cotton  cold,  and  raise  the  temperature  gradually  to  the 
boiling  point.    Wash,  soap,  and  dry. 

In  the  first  bath  the  cotton  simply  absorbs  the  colour- 
ing matter  of  the  Logwood ;  in  the  second  this  is  oxidised, 
and  at  the  same  time  combined  with  a  sufficient  amount  of 
mordant,  copper,  and  chromic  oxide,  to  enable  it  to  take 
up  still  more  colouring  matter  in  the  third  bath.  The 
first  Logwood  bath  is  analogous  to  the  tannin  bath  alluded 
to  in  a  previous  process  (p.  31). 

Logwood  Greys  are  obtained  by  working  the  cotton  for 
a  short  time  at  40°-50°  C.  in  a  weak  decoction  of  Logwood 
(1-5  %),  then  in  a  separate  bath  containing  a  weak  solu- 
tion of  ferrous  sulphate  or  potassium  dichromate,  and 
washing.  Many  dyers  adopt  the  apparently  irrational 
method  of  mixing  the  ferrous  sulphate  and  Logwood  solu- 
tions, and  dye  at  once  in  the  inky  liquid  thus  obtained. 
Comparatively  little  precipitate,  however,  is  produced  in 
the  dye-bath  in  this  case,  and  the  colour  is,  for  the  most 
part,  developed  on  the  cloth  itself  during  the  subsequent 
oxidation  by  exposure  and  washing.  The  shade  of  grey 
may  be  modified  ad  libitum  by  adding  to  the  Logwood 
bath  a  small  proportion  of  decoctions  or  extracts  of  tannin 
matter,  Old  Fustic,  Peachwood,  etc. 

Logwood  Purples  are  obtained  by  mordanting  the 
cotton  in  a  weak  solution  of  stannous  chloride,  then  wash- 
ing and  dyeing  in  a  separate  Logwood  bath.  The  colour 
is  tolerably  fast  to  soap,  but  not  to  light. 


LOGWOOD  COLOURING  MATTERS.  35 


Logwood  Blues  on  cotton  are  now  seldom  dyed,  because 
of  their  fugitive  character.  To  obtain  them,  work  the 
cotton  in  a  bath  containing  a  decoction  of  Logwood  and 
a  small  proportion  of  copper  acetate  or  sulphate,  raising 
the  temperature  gradually  to  50°  C.  The  tone  of  colour 
has  great  similarity  with  that  of  an  indigo-vat  blue. 

Application  of  Ijogivood  to  Wool.—  Logwood  is  the 
essential  basis  of  all  good  blacks  on  wool,  although  other 
colouring  matters  are  frequently  used  along  with  it,  either 
to  modify  the  particular  shade  of  black,  or  to  add  to  its 
intensity  and  permanence. 

According  to  the  materials  employed,  we  may  distin- 
guish the  following  kinds  :  Chrome  black,  copperas  black, 
and  woaded  black. 

Chrome  Blacks  are  produced  by  first  mordanting  the 
wool  for  hour,  at  100°  C,  with  3  %  of  bichromate  of 
potash  and  1  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  184), 
then  washing  and  dyeing  in  a  separate  bath  for  hour, 
at  100°  C,  with  35-50  %  of  Logwood.  This  represents  the 
simplest  form  of  dyeing  a  chrome  black,  but  in  practice 
numerous  slight  modifications  are  introduced,  in  order 
to  obtain  various  shades  of  black.  The  following,  which 
are  typical,  may  be  mentioned.  The  mode  just  given 
yields  a  blue-black,  or,  as  it  is  sometimes  called,  a  black 
with  blue  reflection.  By  the  addition  of  a  suitable 
amount  of  some  yellow  colouring  matter  to  the  dye-bath — 
say,  5  %  Old  Fustic — a  dead-black  is  obtained,  that  is, 
a  neutral  black,  which  possesses  no  decided  tint  of  blue, 
green,  violet,  etc.  By  increasing  the  amount  of  Old 
Fustic  to  10  %,  a  green-black  is  obtained,  and  the  greenish 
shade  becomes  still  more  pronounced  if  3-4  %  of  alum  is 
added  to  the  mordanting  bath  along  with  the  bichromate 
of  potash. 

A  violet-black  is  produced  by  dyeing  exactly  as  for 
blue-black,  but  after  the  dye-bath  has  been  exhausted,  a 
dilute  solution  of  about  2  %  of  stannous  chloride  (tin 
crystals),  or  its  equivalent  of  commercial  muriate  of  tin 
containing  no  free  acid,  is  added  to  the  dye-bath,  and  the 
boiling  is  continued  15-20  minutes  longer. 

In  the  case  of  dead-blacks  it  is  the  custom  with  some 
dyers  to  "  sadden  in  a  similar  way  with  3-4  %  of  fer* 
rous  sulphate;  or,  instead  of  this,  the  goods  are  passed, 


36    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


after  dyeing,  through  a  warm  bath  containing  about  0'5  % 
of  bichromate  of  potash.  The  object  of  these  last  modifica- 
tions is  to  precipitate  and  fix  more  completely  on  the 
wool  any  colouring  matter,  perchance  not  combined  with 
the  mordant,  but  simply  absorbed  by  the  wool. 

With  black  yarn,  which  will  eventually  appear  in  a 
woven  fabric,  in  close  proximity  to  white  or  delicately- 
coloured  yarns,  this  fixing  of  the  dye  is  very  necessary, 
otherwise  the  light-coloured  or  white  yarns  become  stained 
during  the  operations  of  milling,  etc.,  and  the  finished 
fabric  has  a  soiled  appearance.  It  is  always  the  case  that 
some  black  comes  off  during  these  operations,  but  if  the 
colouring  matter  of  the  Logwood  is  thoroughly  combined 
with  its  own  mordant,  it  will  not  readily  combine  with 
the  mordant  of  any  neighbouring  fibre,  but  be  simply 
rubbed  or  washed  out  as  an  insoluble  powder. 

Chrome  blacks  may  also  be  dyed  in  a  single  bath,  as 
follows  :  A  mixture  of  Logwood  liquor  and  bichromate  of 
potash  solution  in  suitable  proportions  is  boiled.  The 
precipitate  thus  produced  is  collected,  and  may  then  be 
employed  as  a  "  direct  black  "  or  a  "  one-dip  dye."  It  is, 
indeed,  the  actual  coloured  body  or  pigment  one  wishes  to 
fix  upon  the  wool,  and  this  is  rendered  possible,  because 
not  only  is  the  precipitate  soluble  in  an  acid  solution,  but 
the  wool  is  capable  of  attracting  it  from  the  solution. 
The  precipitate  is  added  to  the  dye-bath,  along  with  just 
sufficient  oxalic  acid  to  dissolve  it,  and  the  wool  is  dyed  in 
the  solution  at  100°  C,  for  one  and  a  half  hour.  Good 
results  are,  however,  not  so  readily  obtained  as  when  iron 
and  copper  mordants  are  used. 

Indigo  Substitute. — This  product,  at  present  sold  in 
the  form  of  a  purplish-blue  liquid,  is  produced  by  boil- 
ing together  Logwood  extract  and  chromium  acetate. 
Cotton  is  dyed  by  simply  working  it  in  a  hot  solution 
of  the  mixture. 

Of  all  the  blacks  derived  from  Logwood,  the  chrome 
black  is  the  one  least  affected  by  acids.  If  tested  by 
spotting  with  strong  sulphuric  acid,  it  becomes  a  dark 
olive  colour.  It  also  resists  the  action  of  scouring  and 
fulling  very  well.  On  the  other  hand,  however,  chrome 
blacks  are  not  altogether  satisfactory  as  regards  their 
behaviour  on  exposure  to  light.    They  gradually  assume 


LOGWOOD   COLOURING  MATTERS. 


37 


a  greenish  hue,  although  otherwise  they  are  tolerably 
fast. 

The  greening  of  a  chrome  black  is  most  apparent  when 
Logwood,  or  Logwood  and  Old  Fustic,  have  been  employed 
in  dyeing.  Its  bad  effect  may  be  counteracted  by  the 
addition  of  a  suitable  red  colouring  matter  to  the  dye-bath 
— e.g.  Alizarin — or  by  dyeing  the  wool  a  reddish-brown 
colour  before  dyeing  with  Logwood.  This  is  very  con- 
veniently carried  out  in  practice  by  boiling  the  wool  with 
6-8  %  of  Camwood  for  an  hour,  then  adding  to  the  ex- 
hausted bath  the  bichromate  of  potash  (generally  with 
the  addition  of  a  small  percentage  of  alum  and  tartar), 
and  mordanting,  etc.,  as  already  given. 

Owing  to  the  comparatively  small  proportions  of  bichro- 
mate of  potash  required  to  produce  the  fullest  blacks,  there 
is  evidently  a  minimum  quantity  of  lake  precipitated  on 
the  fibre,  so  that  the  latter  retains  very  much  its  pristine 
elasticity  and  softness. 

Excess  of  bichromate  of  potash  should  always  be 
avoided,  since  the  colour  is  then  more  liable  to  become 
green  or  to  fade  on  exposure  to  light. 

Bichromate  of  Potash. — The  following  results  of  ex- 
periments on  the  use  of  chromium  mordants  will  be  of 
interest. 

By  mordanting  the  wool  with  3  %  of  bichromate  of 
potash  a  full  and  bright  shade  is  obtained.  The  use  of 
more  than  this  amount  causes  the  colour  to  become  dull 
and  grey. 

The  employment  of  sulphuric  acid  along  with  the  bi- 
chromate of  potash  is  advantageous  when  the  proportion 
does  not  exceed  one  molecule  of  sulphuric  acid  to  one 
molecule  of  bichromate  of  potash — i.e.  1  %  of  sulphuric 
acid,  168°  Tw.,  to  3  %  of  bichromate  of  potash. 

When  used  in  this  proportion  it  gives  a  brighter  and 
somewhat  deeper  shade  than  can  be  obtained  from  bichro- 
mate alone;  but  should  the  above-mentioned  amount  be 
exceeded,  a  dull  grey  appearance  results,  which  becomes 
more  apparent  as  the  amount  of  sulphuric  acid  increases. 

If  the  bichromate  of  potash  be  increased  along  with 
the  sulphuric  acid,  the  injurious  effects  of  "  over-chrom- 
ing "  are  intensified, 

The  addition  of  tartar  or  tartaric  acid  to  the  mordant- 


38    COLOURING  MATTERS  FOR  DYEING  TEXTILES 


ing  bath,  along  with  bichromate  of  potash,  is  beneficial, 
the  shades  being  much  more  brilliant,  though  somewhat 
lighter,  than  when  sulphuric  acid  is  used. 

Tartaric  acid  gives  decidedly  brighter  and  more  purple 
shades  than  tartar.  The  best  results  are  obtained  by 
using  6  %  of  tartaric  acid  or  8  %  of  tartar  to  3  %  of 
bichromate  of  potash. 

Oxalic  acid  is  also  beneficial  in  the  mordanting  bath, 
and  in  this  case  4  %  of  oxalic  acid  to  3  %  of  bichromate 
of  potash  yields  the  best  results,- 

On  comparing  the  shades  obtained  by  using  these  acids 
in  the  mordanting  bath,  it  is  seen  that  they  are  all  better 
than  can  be  obtained  by  bichromate  of  potash  alone. 

The  addition  of  sulphuric  acid  produces  a  deep,  dead- 
looking  blue-black;  tartar  or  tartaric  acid  yields  a  bright 
bloomy  bluish-black ;  oxalic  acid  a  black  which  is  darker, 
duller,  and  slightly  greener  than  can  be  obtained  with 
tartar  or  tartaric  acid,  but  not  so  dark  as  with  sulphuric 
acid. 

Whenever  bichromate  of  potash  alone  is  employed,  the 
mordanted  cloth  has  a  dull  yellow  colour,  but  if  tartar 
or  tartaric  acid  has  been  added  to  the  bath,  it  is  a  pale 
bluish-green. 

From  these  results  it  would  appear  that  the  best  shade 
is  obtained  when  the  chromium  mordant  is  fixed  on  the 
cloth  in  the  state  of  chromic  oxide  previous  to  the  applica- 
tion of  the  Logwood. 

The  substitution  of  chrome  alum  as  a  mordant  in  place 
of  bichromate  of  potash  does  not  give  good  results,  the 
ultimate  colour  obtained  having  an  irregular  speckled 
appearance,  evidently  owing  to  the  unequal  deposition  of 
the  chromic  oxide;  besides,  a  very  large  proportion  of 
tartar  must  be  used  to  obtain  a  full  shade. 

When  the  cloth  has  been  mordanted  with  bichromate 
of  potash  alone,  or  with  bichromate  of  potash  and  sul- 
phuric acid,  the  presence  of  chalk  or  calcium  acetate  in 
the  dye-bath  is  decidedly  injurious.  The  acetate  seems 
to  be  least  hurtful,  although,  even  with  this,  the  addition 
of  more  than  2  %  gives  the  colour  a  greyish  appearance. 
If  tartar  has  been  employed  along  with  the  bichromate  of 
potash,  the  presence  of  calcium  acetate  is  decidedly  bene- 
ficial, the  shade  being  intensified  from  a  pale  blue  when 


LOGWOOD   COLOURING  MATTERS. 


39 


no  calcium  acetate  is  used  to  a  deep  indigo-blue  when  30  % 
is  employed.  The  best  amount  to  use  appears  to  be  30  %, 
but  even  80  %  may  be  added  to  the  dye-bath  without  any 
great  detriment,  the  colour  merely  losing  a  little  brilliancy 
and  purple  tone,  and  becoming  blacker. 

Copperas  or  Ferrous  Sulphate  Black.—  This-black  was 
formerly  the  one  in  general  use,  but  since  the  introduction 
of  the  chrome  black  it  has  been  more  or  less  discontinued. 
It  is  often  used  for  low-class  carpet  yarns,  etc. 

Two  methods  may  be  employed,  namely,  that  of  mor- 
danting the  wool  first  and  dyeing  afterwards,  or  that  in 
which  the  wool  is  first  boiled  with  Logwood  and  after- 
wards saddened. 

It  is  usual  to  add  along  with  the  ferrous  sulphate  a 
small  proportion  of  copper  sulphate,  and  when  the  first 
method  is  employed,  argol,  and  frequently  also  alum,  is 
added. 

Example  of  First  Method. — Mordant  the  wool  for  l|-2 
hours  with  4-6  %  of  ferrous  sulphate,  2  %  of  copper  sul- 
phate, 2  %  of  alum,  8-12  %  of  arg<  1 ;  take  out,  squeeze, 
and  let  lie  overnight.  Dye  for  l\  1  <iur  with  40-50  %  of 
Logwood. 

Example  of  Second  Method. — Bi  »1  the  wool  for  one 
hour  with  a  decoction  of  40-50  %  of  Logwood  and  5-10  % 
of  Old  Fustic;  lift,  cool  the  bath,  add  4-6  %  of  ferrous 
sulphate,  and  2  %  of  copper  sulphate,  re-enter  the  wool, 
raise  the  temperature  to  100°  C.  in  three-quarters  of  an 
hour,  and  boil  half  an  hour.  The  first  method  is  the 
more  economical. 

The  amount  of  tartar  or  argol  used  along  with  the 
ferrous  sulphate  in  the  first  method  has  considerable 
influence  on  the  beauty  of  the  colour ;  with  too  little  it 
is  grey  and  dull ;  an  excess  is  less  hurtful.  Experiment 
shows  that  the  relative  proportions  should  be  :  1  molecule 
of  ferrous  sulphate,  2-3  molecules  of  cream  of  tartar. 
There  is  no  advantage  in  using  more  than  6  %  of  ferrous 
sulphate.  Wool  mordanted  with  ferrous  sulphate  alone 
is  buff-coloured  from  deposition  of  ferric  oxide ;  when 
tartar  is  used  its  colour  remains  almost  unchanged.  If 
the  water  employed  is  not  calcareous,  the  addition  of  3  % 
of  chalk,  or  preferably  calcium  acetate,  to  the  dye-bath 
increases  the  intensity  of  the  colour.    The  use  of  a  lime 


40    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


salt  here  does  not  appear  to  be  so  effective  as  with 
chromium  or  aluminium  mordants.  As  with  the  chrome 
black,  so  here  the  addition  of  a  yellow  colouring  matter  to 
the  dye-bath  is  necessary  in  order  to  obtain  a  dead-black; 
without  such  additions  a  ferrous  sulphate  black  possesses 
a  bluish-violet  hue.  The  addition  of  relatively  small  pro- 
portion of  Madder,  Sumach,  etc.,  aids  in  giving  a  fuller 
and  faster  black.  Sumach,  or  other  tannin  matter,  when 
used  alone,  is  incapable  of  giving  a  black  on  wool  with 
ferrous  sulphate. 

When  dyeing  unspun  wool  or  yarn  it  is  preferable  to 
use  a  freshly-made  decoction  of  Logwood,  or  a  good  com- 
mercial Logwood  extract,  in  order  to  keep  the  material 
clean  and  free  from  ground  dyewood,  since  this  would 
interfere  in  the  carding. 

The  ferrous  sulphate  blacks  become  red  if  spotted  with 
strong  mineral  acid,  and  are  thus  readily  distinguished 
from  chrome  blacks.  They  bear  the  action  of  scouring 
and  milling  satisfactorily,  and  withstand  the  action  of 
light  better  than  the  chrome  blacks.  Experiment  proves 
that  with  regard  to  fastness  against  light  a  simple  copper 
sulphate  black  is  the  best,  so  that  the  use  of  copper  sul- 
phate along  with  the  ferrous  sulphate  or  potassium  dichro- 
mate  is  distinctly  beneficial.  The  use  of  alum  is,  on  the 
contrary,  detrimental  in  this  respect.  The  copper  sul- 
phate will  probably  also  aid  in  developing  a  fuller  black 
by  reason  of  its  oxidising  action  upon  the  hematoxylin. 

When  employed  alone  copper  sulphate  gives  greenish 
shades  of  blue,  having  a  slightly  speckled  appearance. 
The  best  proportions  to  employ  appear  to  be  5  %  of 
copper  sulphate  and  5  5  %  of  tartar.  An  excess  of  tartar 
causes  the  shade  to  become  much  lighter.  With  these 
amounts,  and  varying  the  quantity  of  Logwood,  a  series 
of  shades,  ranging  from  pale  blue  to  black,  may  be  ob- 
tained, but  the  lighter  shades  have  a  distinct  greenish 
appearance,  when  examined  overhand,  not  observable  in 
the  darker  shades, 

The  mordanting  and  dyeing  method  yields  the  deepest 
and  most  useful  shades.  The  addition  of  lime  salts  to  the 
dye-bath  is  only  slightly  beneficial. 

Bonsor's  Black.— This  "  direct  black/7  originated  by 
P.  Watine-Delespierre,  of  Lille,  consists  of  a  black  paste, 


LOGWOOD  COLOURING  MATTERS. 


44 


produced  by  precipitating  a  decoction  of  Logwood  with 
a  mixture  of  ferrous  and  copper  sulphate.  It  is  applied 
in  the  same  way  as  the  direct  chrome  black  already  re- 
ferred to. 

Add  to  the  dye-bath  25-30  %  of  the  black  paste  and 
about  2-3  %  of  oxalic  acid.  The  wool  is  dyed  at  100°  C. 
for  1-2  hours, 

It  is  essential  that  the  solution  should  not  be  too  acid, 
or  it  will  not  yield  its  full  colouring  power.  The  normal 
colour  of  the  solution  is  dark-brown ;  if  blue  or  green  in 
tint,  it  is  a  sign  of  the  presence  of  undissolved  precipi- 
tate, and  a  further  slight  addition  of  acid  must  be  made. 

As  the  dyeing  proceeds  the  solution  necessarily  becomes 
more  and  more  acid,  and  it  is  well,  before  taking  out  the 
wool,  to  add  a  small  quantity  of  sodium  carbonate  to 
neutralise  the  excess. 

If  a  deeper  shade  is  wanted,  one  may  add  along  with 
the  black  paste  some  extract  or  decoction  of  Logwood. 
For  a  jet-black  or  dead-black  some  suitable  yellow  colour- 
ing matter  may  be  added  in  small  quantity,  e.g.  Old 
Fustic  extract,  etc.  Such  additions,  however,  alter  the 
normal  colour  of  the  solution,  and  a  little  experience  in 
their  use  is  required. 

The  spent  dye  liquor  should  be  kept,  and  may  serve 
again  if  replenished  with  further  quantities  of  black 
paste  and  oxalic  acid- 
It  is  possible  to  use  this  black  along  with  other  so- 
called  acid-colours  for  the  purpose  of  obtaining  composite 
colours,  as  in  the  dyeing  of  unions. 

Woaded  Blacks  are  obtained  by  first  dyeing  the  wool 
in  the  indigo-vat  to  a  light  or  medium  shade  of  blue, 
then  washing  well,  and  dyeing  as  for  chrome  or  ferrous 
sulphate  blacks.  If  the  chrome-black  method  is  selected,  it 
is  advisable  to  make  the  addition  of  tartaric  acid  to  the 
mordanting  bath,  in  order  to  reduce  to  a  minimum  the 
oxidising  action  of  the  bichromate  of  potash,  and  the 
consequent  deterioration  of  the  indigo  blue. 

Logwood  Blues  for  Wool. — These  are  much  employed 
by  dyers,  in  order  to  imitate  an  indigo-vat  blue.  They  are 
often  combined  with  the  latter  by  first  dyeing  the  wool 
a  comparatively  light  blue  in  the  indigo-vat,  and  then 
intensifying  it  bv  one  of  the  methods  now  to  be  described. 


42    COLOURING  MAT  TEE  8  FOR  DYEING  TEXTILES. 


Logwood  blues  are  best  dyed  in  two  baths,  the  mor- 
dants employed  varying  in  composition  and  in  amount 
according  to  the  particular  tint  of  blue  which  it  is  de- 
sired to  obtain. 

One  method  is  as  follows  :  Mordant  the  wool  for  1-1^ 
hour,  at  100°  C,  with  4  %  of  aluminium  sulphate,  4-5  % 
of  cream  of  tartar;  wash  well,  and  dye  in  a  separate  bath 
for  1-1^  hour,  at  100°  C,  with  15-30  %  of  Logwood,  and 
2-3  %  of  chalk. 

By  increasing  the  amount  of  alum  and  tartar  the 
shade  is  made  redder.  The  addition  of  the  chalk,  or  pre- 
ferably calcium  acetate,  to  the  dye-bath  is  very  benjeficial 
if  the  water  employed  is  not  calcareous,  since  it  tends 
to  make  the  colour  level,  and  gives  richness  and  con- 
siderable intensity  to  the  blue.  When  calcium  acetate 
is  employed,  the  best  result  is  obtained  by  using  30  % 
of  the  weight  of  wool.  Some  dyers  imagine  that  the 
use  of  lime  salts  in  dyeing  has  only  a  temporary  effect, 
but  this  is  entirely  a  mistake ;  indeed,  if  distilled  water 
and  Logwood  liquor  be  employed,  the  addition  of  cal- 
cium acetate  to  the  dye-bath  becomes  just  as  absolute  a 
necessity  for  the  production  of  a  good  full  colour  as  it 
is  for  alizarin-red.  The  colour  produced  with  aluminium 
mordants  is  not  fast  to  acids  or  to  light.  This  difference 
in  respect  of  fastness  to  light  with  the  different  mordants 
is  somewhat  remarkable.  A  somewhat  faster  colour  is 
obtained  by  using  along  with  the  alum  and  tartar  0*5-3  % 
of  bichromate  of  potash ;  or,  better  still,  one  may  mordant 
entirely  with  3  %  of  bichromate  of  potash  and  1  %  of 
sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1-84).  If  it  is  desired 
to  imitate  the  purplish  tint  of  a  vat  indigo  blue,  one  may 
then  add  to  the  dye-bath,  along  with  the  Logwood,  a  small 
proportion  of  Gallein,  Alizarin,  Galloycyanin,  etc. 
Another  method  of  imparting  this  purplish  "  bloom  "  is 
to  add  0  5-1  %  of  tin  crystals  (SnCl2'2H20)  at  the  end  of 
the  dyeing  operation. 

The  brightest  Logwood  blues  are  obtained  by  dyeing 
at  a  temperature  somewhat  below  the  boil  (90°  C.).  Pro- 
longed boiling  tends  to  dull  the  colour. 

Logwood  Purples  for  Wool.—  These  are  now  seldom 
used.  They  may  be  obtained  by  mordanting  the  wool  with 
6  %  of  tin  crystals  (SnCl2*2H20),  or  its  equivalent  of 


LOGWOOD   COLOURING  MATTERS, 


muriate  of  tin,  with  the  addition  of  9  %  of  cream  of  tar- 
tar, and  dyeing  in  a  separate  bath  with  30  %  of  Logwood. 
The  addition  of  chalk  or  calcium  acetate  to  the  dye-bath 
in  this  case  is  injurious,  since  it  makes  the  colour  greyer 
and  less  intense. 

A j) plication  to  Silk. — The  black  dyeing  of  silk  has  in- 
creased to  such  an  enormous  extent  that  some,  and  even 
very  large,  establishments  are  exclusively  devoted  to  it. 
Judged  from  the  technical  standpoint,  it  must  be  admitted 
that  this  branch  has  reached  a  high  standard  of  excellence, 
although,  on  the  other  hand,  it  is  to  be  regretted  that 
the  practice  of  weighting  silk,  which,  in  the  case  of  black, 
may  reach  as  high  as  600  %,  has  been  so  much  developed. 
From  100  kg.  =  220  lb,  of  raw  silk  the  dyer  can  pro- 
duce 700  kg.  =  1,540  lb.  of  black  silk  !  The  primary  ob- 
ject is  to  increase  the  volume  of  the  silk  fibre,  which  swells 
up  very  considerably,  losing,  of  course,  its  strength  pro- 
portionally. The  other  valuable  properties  of  silk  are 
also  more  or  less  deteriorated,  and  the  illusory  gain  of 
the  buyer  is  that  he  requires  to  pay  less  for  one  and  the 
same  surface  of  silk  material.  On  the  other  hand,  fashions 
now  have  such  a  short  life  that  the  tendency  is  to  desire 
something  which  is  cheap  and  can  soon  be  replaced ;  so 
that  silk,  weighted  in  reason,  has  its  advocates. 

The  production  of  black  on  silk  consists  in  alternating 
treatments  with  iron  mordant  and  tannin  matters,  with 
or  without  a  Prussian  blue  basis. 

According  to  Messrs.  Gillet  &  Son,  the  present  methods 
of  dyeing  black  silk  may  be  classified  in  six  divisions,  as 
follows  : — 

Black  on  Boiled-off  Silk,  5-15  %  loss.  A.  Black 
for  Hat  Plush.— I.  Mordant  in  cold  nitrate-acetate 
of  iron,  and  wash.  2.  Dye  in  a  decoction  of  Log- 
wood and  a  sufficiency  of  Old  Fustic  extract.  As  a  rule, 
1-2  %  of  copper  acetate  and  5-10  %  of  ferrous  sulphate 
are  added  to  this  bath.  3.  Dye  again  in  a  decoction  of 
Logwood  and  soap.  4.  Brighten  in  a  bath  containing  a  lit- 
tle oil.  B.  M assorts  Black  for  Hat  Trimmings. — These  are 
exclusively  Parisian  goods,  and  of  limited  use.  The  silk  is 
boiled-off  in  soap  containing  Logwood  decoction,  by  which 
means  it  is  rendered  less  liable  to  felt.  It  is  mordanted 
in  a  solution  of  partially  oxidised  ferrous  sulphate,  with 


44    COLOURING  MATTERS  FOR  DYEING  TEXTILES 


addition  of  a  little  copper  acetate,  and  afterwards  dyed 
with  Logwood  and  soap. 

C.  English  Black. — Formerly  in  great  demand,  this 
black  is  now  of  minor  importance.  1.  Mordant  with  basic 
ferric  sulphate,  and,  after  allowing  the  silk  to  lie  for  some 
time,  wash  well  and  soap  at  85°-90°  C.  2.  Dye  with  50  % 
of  Old  Fustic,  10  %  of  ferrous  sulphate,  and  2  %  of  copper 
acetate.    3.  Dye  with  Logwood  and  soap.    4.  Brighten. 

D.  Black  for  Velvets. — The  same  method  as  for  English 
black  is  used,  but  dye  a  lighter-coloured  black.  The  tone 
of  colour  is  frequently  modified  by  giving  the  silk  pre- 
viously a  dark  ground  of  aniline  violet  or  blue.  Great 
care  is  required  in  order  not  to  strip  off  the  aniline  blue. 

Black  on  Boiled-off  Silk,  original  weight  or  weighted 
10  %.  E.  Lyons  Black  (dating  from  1860),  for  expensive 
articles. — 1.  Mordant  in  a  cold  strong  bath  of  basic  ferric 
sulphate,  50°  Tw.  (Sp.  Gr.  125),  once  only,  and  wash. 
2.  Soap  at  85°-90°  C.  3.  Dye  blue  with  15-20  %  of  potas- 
sium ferrocyanide  and  an  equal  weight  of  hydrochloric 
acid,  30°  Tw.  (Sp.  Gr.  115).  Add  the  hydrochloric  acid  in 
two  separate  portions.  4.  Mordant  with  basic  ferric  sul- 
phate, and  wash.  5.  Give  a  Catechu  bath,  50-100  %,  at 
60°-80°  C.  6.  Mordant  in  a  cold  solution  of  alum  or 
aluminium  sulphate,  and  wash.  The  object  of  using  alu- 
minium mordant  is  to  impart  ultimately  to  the  silk  a 
violet  or  blue-black  shade.  7.  Dye  with  Logwood  and  soap. 
If  shade  is  too  violet,  a  little  Old  Fustic  is  added.  8. 
Brighten. 

F.  Mineral  Black  (dating  from  1840). — This  is  a  light 
black,  not  so  fine  as  the  last,  and  is  used  for  "  linings.'7 
Mordant  with  basic  ferric  acetate,  and  wash ;  dye  Prussian 
blue;  repeat  the  mordanting  with  iron.  Prepare  with 
Catechu  (100  %)  at  80°  C.  Dye  with  Logwood  and  soap. 
Brighten. 

Black  on  boiled-off  Silk,  weighted  20-100  %  (heavy 
black).  G.  This  black  is  dyed  on  organzine  and  tram  for 
satins,  sarcenets,  taffetas,  etc.  1.  Mordant  with  basic  ferric 
sulphate,  then  soap.  Repeat  these  operations  1-8  times,  ac- 
cording to  the  amount  of  weighting  necessary.  2.  Dye 
blue;  the  proportions  of  potassium  ferrocyanide  and 
hydrochloric  acid  vary  according  to  the  amount  of  ferric 
oxide    fixed    on    the    silk.    3.  Give    a    Catechu  bath 


LOGWOOD  COLOURING  MATTERS. 


it 


(100-150  %),  with  the  addition  of  10-15  %  stannous 
chloride,  at  60°-80°  C.  The  employment  of  stannous 
chloride  in  weighted  black-silk  dyeing  has  been  of  the 
greatest  importance,  since  it  facilitates  the  fixing  of  the 
Catechu  to  a  surprising  degree,  through  the  formation  of 
a  tannate  of  tin.  4,  Give  a  second  bath  of  Catechu 
(100-200  %).  This  is  fixed  on  the  silk  only  by  the  action 
of  the  tin  mordant  present.  5.  Mordant  with  pyrolignite 
of  iron.  6.  Dye  with  Logwood  and  soap.  7.  Brighten. 
Blue  shades  of  black  are  obtained  by  repeating  operations 
5,  4,  6,  in  the  order  given,  four  times.  The  only  factors 
which  affect  the  limitation  of  weighting  are  the  strength, 
elasticity,  and  lustre  of  the  silk  itself.  As  a  rule,  boiled- 
off  organzine  is  weighted  to  60-70  %,  and  boiled-off  tram  to 
100  %. 

Heavy  Black,  weighted  to  400  %.  H.  This  is 
used  for  fringes  and  the  fancy  articles  of  Paris  and 
Lyons ;  also  for  the  tram  silk  for  satin,  cheap  rib- 
bons, etc.  The  raw  silk  is  dyed  by  working  it  alter- 
nately in  chestnut  extract  and  pyrolignite  of  iron. 
By  repeating  these  operations  fifteen  times,  the  silk  is 
weighted  to  about  400  %.  The  final  processes  consist  of 
brightening  operations  with  10-20  per  cent,  of  olive-oil. 
In  the  first  chestnut  extract  bath,  tram  is  soupled  by 
raising  the  temperature  of  the  bath  sufficiently  to  soften 
the  silk-glue.  Different  qualities  of  silk  require  slightly 
different  treatment.  Bengal  silk  souples  easily ;  Chinese 
silk  less  readily  than  European  silk. 

Fine  Black  Souples.  I.  The  finest  souples  arc 
always  obtained  by  using  water  as  soft  as  possible, 
like  that  of  the  Gier  at  Saint-Chamond.  1.  Mordant 
with  basic  ferric  sulphate.  2.  Give  a  soda  bath  at 
30°-40°  C.  Use  50  %  of  carbonate  of  soda  crystals. 
3.  Dye  blue  with  potassium  ferrocyanide.  4.  Souple  by 
working  in  a  bath  of  gall-nuts,  dividivi,  or  other 
similar  tannin  matter.  Heat  the  bath  to  90°-95°  C, 
for  1-3  hours,  according  to  the  kind  of  silk.  Experience 
alone  enables  the  workman  to  judge  when  the  softening 
or  soupling  is  sufficient.  5.  Leave  the  silk  in  No.  4  bath 
until  cold,  and  then  add  5-15  %  of  stannous  chloride  cry- 
stals. 6.  Give  a  soap  bath  at  30°-35°  C,  with  60-80  % 
of  soap.    7.  Brighten  with  5-15  %  of  oil.    A  single  iron 


46    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


bath  gives  40-50  %  of  weighting  (light  souple)  ;  two  baths 
give  60-70  %  ;  three  give  80  %  ;  four  give  80-100  %. 

Black  on  Raw  Silk.  J.  Raw  silk  is  seldom  dyed.  In 
order  to  retain  the  stiffness  of  the  silk,  the  silk-glue  is  not 
softened,  the  number  of  operations  is  as  limited  as  possi- 
ble, and  the  various  bath  are  used  at  a  low  temperature. 
The  process  consists  of  working  the  silk  in  baths  of 
ferric  salt,  then  in  decoctions  of  Logwood  and  Old 
Fustic.  For  boiled-off  silk  the  potassium  ferrocyanide 
baths  are  employed  at  a  temperature  of  55°-60°  C,  be- 
cause the  formation  of  Prussian  blue  would  otherwise  pro- 
ceed only  very  slowly,  creeping,  as  it  were,  from  the 
periphery  to  the  centre  of  the  fibre.  For  souple  silks, 
however,  it  is  necessary  to  use  cold  baths.  Only  a  portion 
of  the  requisite  hydrochloric  acid  is  at  first  added,  in 
order  to  avoid  dissolving  off  any  basic  ferric  sulphate. 

The  operation  of  brightening  is  intended  to  restore 
the  soft  feel  and  lustre,  which  have  been  greatly  destroyed 
by  reason  of  the  large  amount  of  foreign  matter  with 
which  the  silk  has  become  encrusted.  For  boiled-off  silk 
there  is  used  about  1-2  %  of  olive  oil;  for  souples,  5-15  %  ; 
and  for  fringes,  etc.,  5-20  %.  The  oil  is  made  into  an 
emulsion  with  carbonate  of  soda  at  60°-70°  C,  or  with 
caustic  potash  or  soda  in  the  cold,  and  then  immediately 
mixed  in  the  bath  with  water.  The  silk  must  be  worked 
in  the  mixture  at  once,  i.e.  before  any  separation  of  the 
oil  can  take  place.  Very  often  an  addition  is  made  of 
40-60  %  of  citric,  tartaric,  or  acetic  acid. 

The  usual  duration  of  each  operation  varies  from  1-2 
hours,  but  in  the  tannin  baths  the  silk  should  remain 
longer ;  it  is  frequently  left  steeping  in  them  over-night. 

The  black  dyeing  of  Tussur  silk  is  a  difficulty  not  yet 
completely  overcome.  The  shades  are  not  satisfactory, 
and  the  fibre  becomes  covered  with  metallic-looking  spots. 

1.  Boil-off  with  dilute  caustic  soda.  2.  Mordant  once 
or  twice  in  basic  ferric  sulphate,  and  fix  by  means  of  a 
bath  of  weak  caustic  soda.  3.  Dye  with  potassium  ferro- 
cyanide. 4.  Prepare  with  a  weak  chestnut  extract  bath. 
5.  Mordant  with  pyrolignite  of  iron,  and  repeat  opera- 
tions 4  and  5.    6.  Brighten  with  6-8  %  olive  oil. 


47 


CHAPTER  III. 

NATURAL  RED  AND  YELLOW   COLOURING  MATTERS. 

Brazil  wood,  Peachwood,  and  Limawood. — Obtained  from 
various  species  of  Ccesalpinia,  and  their  dyeing  properties 
were  similar,  but  owing  to  the  fugitive  colours  they  gave 
they  were  seldom  used  except  for  shading  purposes,  and 
have  now  been  largely  replaced  by  artificial  dyes.  Applica- 
tion to  cotton  :  With  aluminium  mordants  dull  bluish-red 
colours  were  obtained;  stannic  mordants  gave  brighter 
and  more  orange-toned  reds;  and  iron  mordants  gave 
violet-grey  shades.  Application  to  wool  :  A  mordant  of 
bichromate  of  potash  gave  a  purplish-slate  colour  if  used 
in  small  quantities,  and  a  claret  brown  with  larger  quan- 
tities ;  aluminium  sulphate  gave  a  bluish-red  colour, 
which  could  be  made  bluer  by  ammonia;  stannous  and 
stannic  chloride  yielded  bright  reds;  copper  sulphate, 
drab  or  claret  brown  shades;  and  ferrous  sulphate  dark 
slate  and  claret.  Application  to  silk  :  Crimson  shades 
were  obtained  with  alum,  and  bright  crimsons  by  stannous 
chloride. 

Camwood,  Barwood,  and  Sanderswood. — Obtained  from 
certain  species  of  Pterocarpus  and  Baphia,  and  are  simi- 
lar in  dyeing  properties  but  different  in  tone.  Applica- 
tion to  cotton  :  Aluminium  and  tin  mordants  gave  good 
reds,  and  good  chocolate  or  violet  brown  shades  were 
obtained  with  pyrolignite  of  iron.  Application  to  wool  : 
Rich  claret  brown  shades  were  obtained  with  bichromate 
of  potash,  dull  brownish-red  shades  with  aluminium, 
brighter  and  bluer  reds  with  stannous  chloride,  claret 
brown  with  copper  sulphate,  and  purplish  shades  with 
ferrous  sulphate. 

Madder.—  Obtained  from  the  dried  roots  of  Eubia 
tinctorum,  and  although  once  perhaps  the  most  useful 
dyestuff,  has  now  been  entirely  replaced  by  artificial 
Alizarin. 

Cochineal.—  Obtained   from   the   dried   insect  Coccus 


48    COLOURING  MATTERS  FOR  DYEING  TEXTILES, 


cacti,  but  has  been  replaced  by  the  azoreds,  and  is  now 
only  used  in  exceptional  cases. 

Orchil. — Prepared  from  certain  lichens  by  oxidising 
them  in  the  presence  of  ammonia.  It  is  still  sometimes 
used  for  wool  and  silk,  being  dyed  with  the  former  with 
a  little  sulphuric  acid,  and  the  latter  in  a  soap  solution. 
The  colour  produced  is  a  bright  bluish-red  or  magenta. 

Annatto. — Obtained  from  the  pulp  surrounding  the 
seeds  of  Bixa  orellana,  and  is  only  used  to  a  very  limited 
extent  in  silk  dyeing  with  the  addition  of  soap.  Pale 
shades  are  obtained  at  50°  C.  and  dark  ones  at  80°-100°  C, 
but  they  are  of  a  fugitive  character. 

Safflower. — The  dried  florets  of  Carthamus  tinctorius, 
and  yields  a  bright  but  fugitive  pink  on  all  fibres. 

Weld. — The  plant  Reseda  luteola,  and  was  used  for 
yellow  and  olive  colours  on  wool  and  silk,  but  chiefly  for 
silk,  and  for  certain  colours  it  is  still  used  on  that  fibre. 
It  is  dyed  on  silk  which  has  been  mordanted  with  alum 
with  20-40  %  Weld  at  50°-60°  C. 

Old  Fustic. — The  wood  of  Morus  tinctoria,  and  was 
never  used  much  for  cotton.  Applied  to  wool  :  With 
bichromate  of  potash  old  gold  shades  are  obtained ; 
aluminium  mordant  gives  yellow  shades,  and  bright  fast 
colours  can  be  obtained  with  stannous  mordant.  It  is 
applied  to  silk  for  a  light  yellow  by  working  for  J-J  hour, 
at  50°-60°  C,  in  a  bath  containing  16  %  alum  and  8-16  % 
Old  Fustic. 

Quercitron  Bark. — The  inner  bark  of  Quercus  tinctoria, 
and  was  never  used  much  for  cotton  or  silk  dyeing.  Ap- 
plied to  wool  :  Bichromate  of  potash  gives  reddish-olive 
yellows,  aluminium  yellows  are  paler,  and  stannic  chloride 
gives  a  pale  buff  colour. 

Flavin. — A  preparation  of  Quercitron  Bark  which 
gives  stronger  colours. 

Young  Fustic. — The  wood  of  the  sumach  tree  (Rhus 
cotinus)  which  was  once  used  largely  in  silk  dyeing,  and 
still  is  very  occasionally  used  for  certain  oranges  and 
scarlets  on  wool.  Bichromate  of  potash  gives  a  reddish 
brown,  aluminium  mordants  produce  yellowish  buffs, 
bright  yellows  are  obtained  with  stannous  mordants,  whilst 
copper  and  iron  mordants  give  olive  shades. 

Persian  Berries. — The  dried  unripe  fruit  of  Rhamnus, 


YELLOW  COLOURING  MATTERS.  49 


which  were  chiefly  used  for  printing  olive,  orange,  and 
green  shades  on  cotton. 

Turmeric. — The  tuber  of  Curcuma  tinctoria,  which 
yields  a  bright  yellow  on  cotton  without  the  aid  of  a  mor- 
dant. It  can  also  be  used  on  wool  without  a  mordant, 
but  gives  darker  shades  with  aluminium  and  more  orange 
ones  with  tin. 

Barberry. — The  root  and  bark  of  Berberis  vulgaris, 
and  was  never  used  beyond  silk  and  leather  dyeing,  giving 
light  shades  with  sulphuric,  acetic,  or  tartaric  acids,  and 
dark  ones  with  stannous  chloride. 

Catechu. — Obtained  from  species  of  acacia,  areca,  and 
uncaria,  and  was  once  largely  used  for  various  brown 
to  black  shades  on  cotton  and  for  black  on  silk.  It  has 
not  yet  been  entirely  replaced  by  artificial  dyestuffs.  On 
cotton  it  is  applied  with  bichromate  of  potash  or  alu- 
minium, but  it  was  never  much  used  for  wool. 


t) 


50 


CHAPTER  IV. 

ANILINE  COLOURING  MATTERS. 

Recent  years  have  brought  about  a  great  change  in  dyeing 
methods,  this  being  caused  not  only  by  the  introduction  of 
artificial  colouring  matters  but  by  the  way  in  which  it 
has  been  possible  to  substitute  their  use  in  practically 
every  case  where  natural  colouring  matters  were  previ- 
ously employed.  One  by  one  the  old  dyes  have  been  sup- 
planted, and  it  is  only  in  certain  cases  where  their  use 
has  its  advantages  for  obtaining  some  special  result. 
Even  natural  Indigo,  which  only  recently  was  supposed 
to  be  unique  for  certain  purposes  and  quite  impossible  to 
replace,  is  now  finding  its  place  gradually  usurped  by 
synthetic  Indigo.  There  are  a  large  number  of  artificial 
dyestuffs  which  are  cheap  but  fugitive,  and  these  find  their 
uses  in  low  goods  which  are  not  expected  to  be  long  in  use, 
but,  on  the  other  hand,  the  colours  previously  obtained  by 
natural  dyestuffs  can  now  be  obtained,  in  many  instances, 
by  cheaper  and  easier  methods  and  with  better  results. 

Although  there  are  now  hundreds  of  brands  of  artifi- 
cial dyes,  these  are  being  added  to  at  the  rate  of  a  few 
a  week,  so  that  no  attempt  will  be  made  here  to  accomplish 
the  impossible  task  of  enumerating  them'  all.  The  earlier 
and  principal  brands  are  therefore  mentioned,  as  these 
not  only  form  the  basis  of  other  and  later  colours,  but 
many  so-called  new  dyes  are  nothing  but  mixtures  of  old 
ones. 

(a.)    Rosaniline  Group. 

I  C6H4-N(CH3)2 
Benzaldehyde  Green.    C  <  q6h5 

(  N(CH3),C1 

This  colouring  matter  is  derived  from  dimethyl-aniline, 
and  this  is  the  hydrochloride  of  tetra-methyl-diamido- 
triphenyl-carbinol.  In  commerce  it  occurs  really  as  vari- 
ous salts  (sulphates,  oxalates,  etc.),  or  zinc  double  salts 
of  the  colour-base,  and  is  sold  under  a  variety  of  names, 


ANILINE   COLOURING  MATTERS.  51 


e.g.  Malachite  Green  [3(C23H24N2-HCl)2ZnCl2'2H20]  (Ber- 
lin Aniline  Co.),  Solid  or  Fast  Green  [2C23H24N2- 
•3C2H2OJ  (L.  Cassella  &  Co.),  Victoria  Green  (Badische 
Anilin  and  Soda  Fabrik),  Benzoyl  Green,  New  Green,  etc. 
Closely  allied  colouring  matters  possessing  similar  dyeing 
properties  are  those  derived  from  diethyl-aniline,  and 
known  as  Ethyl  Green,  Fast  Green  J,  New  Victoria  Green 
OG  (basf),  Brilliant  Green,  etc.  They  give  yellower 
shades  of  green  than  those  derived  from  dimethyl-aniline. 
In  dyeing  with  all  these  greens,  the  temperature  of  the 
dye-bath  may,  if  necessary,  be  raised  to  100°  C.  without 
injuring  the  colour. 

Application  to  Cotton. — Prepare  the  cotton  with  tannic 
acid  and  tartar  emetic,  wash,  and  dye  in  a  fresh  bath. 
The  dye-solution  may  be  cold  or  it  may  be  heated  gradually 
to  a  temperature  not  exceeding  60°  C.  Add  the  colour 
solution  (2-4  %)  gradually.  The  dye-bath,  which  is  some- 
times very  slightly  acidified  with  acetic  acid,  is  not  ex- 
hausted, and  should  be  preserved  for  fresh  lots  of  material. 

For  bright .  shades  the  cotton  may  be  prepared  with 
sulphated  oil  and  aluminium  sulphate. 

For  yellow  shades  of  green  add  to  the  dye-bath  Aura- 
mine  or  other  basic  yellow  colouring  matter.  One  may 
also  mordant  with  aluminium,  fix  with  phosphate  of  soda, 
and  dye  first  with  Quercitron  Bark  and  then,  in  a  separ- 
ate bath,  with  Benzaldehyde  Green. 

Jute  is  dyed  with  this  and  all  basic  colouring  matters 
without  being  mordanted. 

Application  to  Wool. — Dye  in  a  neutral  bath,  that  is, 
without  any  addition  other  than  the  colour-solution.  The 
custom  of  adding  soap  to  the  dye-bath  is  not  to  be  recom- 
mended, because  of  the  formation  of  insoluble  sticky  zinc 
soap.  An  addition  of  at  most  1-2  %  of  sulphuric  acid, 
168°  Tw.  (Sp.  Gr.  1*84),  alum,  or  other  acid  salt,  may  be 
made  under  special  circumstances.  The  colour  shows  a 
great  tendency  to  rub  off,  and  does  not  withstand  the 
action  of  milling  or  of  light.  Better  results  in  all  these 
respects  are  obtained  by  mordanting  the  wool  previously 
with  thiosulphate  of  soda,  according  to  the  method  given 
for  Methyl  Green. 

Application  to  Silk. — Dye  at  a  temperature  of 
50°-60°  C.  in  a  bath  containing  a  small  quantity  of  soap, 


52    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


or  "  boiled-off  "  liquor.  Sometimes  a  little  sulphuric  acid 
is  added  to  the  bath.  Wash  well,  brighten  in  a  cold  bath 
very  slightly  acidulated  with  acetic  acid,  and  dry. 

For  yellow  shades  of  green,  add  to  the  dye-bath  Aura- 
mine  or  other  basic  yellow  colouring  matter.  If  Picric 
Acid  or  other  acid  colour  is  used,  it  must  be  added  to  the 
brightening  bath,  taking  care  not  to  use  any  excess  of 
acetic  acid,  otherwise  the  green  will  be  stripped  off.  It 
is  better  to  dry  the  silk  at  once  after  brightening,  in  order 
not  to  remove  any  Picric  Acid  by  rinsing. 

Acid  Green. — Several  acid  greens  are  met  with  in  com- 
merce, bearing  such  names  as  Helvetia  Green  (Soc.  Chem. 
Ind.,  Basle),  Acid  Green  (Poirrier),  Light  Green  S  (basf), 
Guinea  Green  (Berlin  Aniline  Co.),  etc.  They  are  sodium 
or  calcium  salts  of  the  sulphonic  acids  of  the  base  of  one 
or  other  of  the  Benzaldehyde  Greens. 

As  their  name  implies,  they  require  to  be  applied  in 
an  acid  bath.  Their  dyeing  power  is  less  than  that  of 
the  Benzaldehyde  Greens,  but,  employed  with  other  acid 
colours,  they  are  extremely  useful  for  producing  compound 
shades.    They  are  not  suitable  for  dyeing  cotton. 

Application  to  W ool. — Dye  with  the  necessary  amount 
of  colour  and  2-3  times  its  weight  of  sulphuric  acid, 
168°  Tw.  (Sp.  Gr.  1'84),  added.  An  addition  of  10-20  % 
of  sodium  sulphate  may  also  be  made  if  there  is  any 
tendency  to  uneven  dyeing.  Raise  the  temperature  gradu- 
ally to  near  the  boiling  point. 

Application  to  Silk. — Dye  at  a  temperature  of  50°  C. 
with  the  addition  of  "  boiled-off  ,?  liquor  slightly  acidified 
with  sulphuric  acid. 

Alkali  Green,  Viridin. — This  colouring  matter,  derived 
from  diphenylamine  by  the  Malachite  Green  process  or  pre- 
pared by  oxidising  benzyl-diphenylamine  with  chloranil, 
is  only  of  limited  use.  Being  a  sodium  sulphonate  of  the 
colour-base,  its  dyeing  properties  are  similar  to  those  of 
Alkali  Blue,  and  it  is  applied  in  exactly  the  same  way. 
Pleasing  greenish  shades  of  blue  may  be  obtained  on  wool 
by  using  mixtures  of  Alkali  Blue  and  Alkali  Green. 

(  CfiH4-NH2 
Magenta.  Oj§g™^ 
(  NH./C1 


ANILINE   COLOURING  MATTERS. 


53 


This  colouring  matter,  sometimes  called  Roseine,  Ponceau, 
Rubine,  etc.,  is  usually  the  hydrochloride  or  the  acetate  of 
the  organic  base  tolyl-diphenyl-triamido-carbinol  or 
rosaniline.  Various  bye-products,  containing  impure 
Magenta,  are  sold  under  different  names,  e.g.  Cerise, 
Grenadine,  Cardinal,  Amaranth,  etc.  None  of  these  yield 
dyes  which  are  fast  to  light. 

Application  to  Cotton. — Prepare  the  cotton  with  tan- 
nic acid,'  and  either  tartar  emetic  or  stannic  chloride, 
wash  well,  and  dye  in  a  separate  bath  at  45°-50°  C.  Add 
the  colour  solution  to  the  batK  gradually.  In  conjunc- 
tion with  other  basic  colouring  matters — e.g.  Chryoidine, 
Neutral  Violet,  etc. — numerous  compound  shades  (claret, 
bordeaux,  etc.)  can  be  obtained. 

Brighter  colours  are  obtained  by  mordanting  the  cotton 
with  sulphated  oil  and  aluminium  sulphate,  but  they  are 
not  so  fast  to  soap  as  those  fixed  by  means  of  tannic  acid. 
Both  methods  are  applicable  to  all  basic  colouring  matters. 

Application  to  Wool. — Dye  in  a  neutral  bath.  Heat 
gradually  to  90°  C.  With  the  addition  of  2-4  %  of  soap, 
the  colour  obtained  is  brighter ;  but,  in  this  case,  the  bath 
cannot  be  exhausted,  and  should  be  preserved,  if  possible, 
for  subsequent  lots  of  woollen  material.  This  is  the 
general  mode  of  dyeing  with  all  basic  colouring  matters. 

The  colour  bleeds  in  milling,  and  is  not  suitable  for 
"  Tweed-yarns, "  etc. 

Application  to  Silk.— Dye  at  50°-60°  C.  in  a  weak, 
fresh,  soap  bath,  adding  the  colour  solution  gradually. 
Wash  and  brighten,  for  yellow  shades,  in  a  bath  slightly 
acidulated  with  acetic  or  tartaric  acid;  for  blue  shades 
acidify  with  sulphuric  acid. 

Acid  Magenta.— This  colouring  matter  is  the  sodium 
salt  of  the  trisulphonic  acid  of  rosaniline.  It  has  only 
about  half  the  colouring  power  of  Magenta,  and  is  not 
applicable  in  cotton-dyeing. 

Application  to  Wool.— Bye  in  a  bath  acidified  with 
2-4  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84),  with  the 
addition  of  20-30  %  of  sodium  sulphate  if  there  is  any 
tendency  to  irregular  dyeing.  Introduce  the  textile 
material  at  40°  C,  raise  the  temperature  to  100°  C.  in 
40  minutes,  and  boil  20-30  minutes.  This  is  the  general 
mode  of  dyeing  with  all  similar  acid  colours. 


54    COLOURING  MATTERS  FOR  DYEING  TEXTILES 


Acid  Magenta  is  much  used  in  conjunction  with  other 
colouring  matters  applied  in  an  acid  bath  for  dyeing 
compound  shades.  The  colour  it  yields  is  decolorised  by 
the  action  of  alkalis,  and  is  not  suitable  for  goods  re- 
quiring to  be  milled. 

Application  to  Silk. — Dye  in  a  bath  containing 
"  boiled-off  "  liquor  slightly  acidulated  with  sulphuric 
acid.    Add  the  colour  solution  gradually. 


This  colouring  matter,  in  its  purest  form,  is  the  hydro- 
chloride of  tri-phenyl-rosaniline.  According  to  its  purity, 
this  blue  yields  shades  which  vary  from  a  dull  reddish- 
blue  to  a  pure  sty-blue.  The  redder  shades  are  marked  R 
(Dahlia,  Parma  Blue,  etc.),  while  those  marked  5  B  and 
6  B  (Opal  Blue,  Lyons  Blue,  etc.),  give  the  purer  shades. 
Intermediate  products  are  marked  B,  2  B,  3  B,  4  B  (Hum- 
boldt Blue,  Imperial  Blue,  Gentiana  Blue,  etc.). 


This  colouring  matter,  derived  from  diphenylamine,  is 
considered  as  the  hydrochloride  of  tri-phenyl-para- 
rosaniline.  It  is  a  somewhat  finer  but  also  more  expensive 
blue. 

Methyl  and  Ethyl  Blue. — These  are  methyl  and  ethyl 
derivatives  of  Diphenylamine  Blue,  and  are  distinguished 
by  the  extreme  purity  of  the  greenish-blue  colour  which 
they  yield. 

These  spirit  colours  are  dissolved  in  40-50  times  their 
weight  of  methylated  spirit,  sometimes  with  the  addition 
of  a  very  little  sulphuric  acid.  Use  a  narrow-necked 
vessel,  and  heat  by  placing  it  in  hot  water. 

Application  to  Cotton. — The  cotton  is  prepared  with 
oleate  of  alumina.  Work  the  bleached  cotton  in  a  hot 
(60°  0.)  soap  bath  (60-100  g.  =  1*9-3  2  ozs.  of  soap  per  kg.  == 
2*2  lb.  of  cotton),  squeeze,  and  work  in  a  cold  bath  of 
aluminium  acetate,  8°  Tw.  (Sp.  Gr.  1'04),  and  squeeze. 


Spirit  Blues  :  Rosaniline  Blue.  C 


(  C6H4-NH(CfiH5) 
)  C6H4-NH(C6H5) 
)  CgH3*CH3 
(  NH-C6H5-C1 


Diphenylamine  Blue.  C 


ANILINE  COLOURING  MATTERS.  55 


Repeat  these  operations  three  times,  and  dye  in  a  fresh 
bath.  One  may  also  work  the  soaped  cotton  at  once  in 
a  dye-bath  to  which  aluminium  acetate  has  been  added. 
Add  the  colour  solution  in  small  portions,  and  heat  gradu- 
ally to  the  boiling  point.  Wash  well  in  cold  water,  and 
pass  finally  through  a  weak  soap  bath,  heated  to  60°  C, 
to  which  a  little  acetic  acid  has  been  added  till  it  just 
begins  to  show  signs  of  turbidity. 

Cotton  may  also  be  prepared  with  tannic  acid,  and 
dyed  in  a  fresh  bath  containing  colour-solution  and 
acidified  with  alum. 

Application  to  Wool.— Dye  with  1-5  %  of  colouring 
matter  (or  more  if  necessary),  with  the  addition  of  4-8  % 
of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  T84),  and  10-20  % 
of  sodium  sulphate.  Enter  the  wool  at  50°-60°  C,  heat  up 
rapidly  to  100°  C,  and  boil  \  hour,  or  longer  if  necessary. 
The  acid  and  also  the  colour  solution  should  be  added 
gradually  to  the  bath,  and  in  small  portions  at  a  time, 
in  order  to  ensure  a  regular  colour.  Instead  of  sulphuric 
acid  one  may  also  acidify  with  10-12  %  of  alum. 

When  red  shades  of  blue  are  used,  trie  addition  of 
sulphuric  acid  gives  the  best  colour ;  with  the  purer  blues 
brighter  shades  are  obtained  with  the  use  of  alum. 

Owing  to  their  insolubility,  Spirit  Blues  are  very  apt 
to  dye  unevenly,  but  they  are  preferred  by  yarn-dyers 
when  the  goods  have  subsequently  to  be  milled'. 

Application  to  Silk. — Introduce  the  silk  into  a  tepid 
bath  containing  "  boiled-off  ;;  liquor  acidified  with  sul- 
phuric acid.  Add  the  colour  solution  by  degrees,  heat 
gradually  to  100°  C,  and  dye  at  this  temperature.  Wash 
in  cold  water  and  brighten  with  dilute  sulphuric  acid. 

Soluble  Blues. — The  Soluble  Blues  generally  consist  of 
the  ammonium  or  sodium  salts  of  the  di-  and  ^W-sulphonic 
acids  of  Rosaniline  or  Diphenylamine  Blues.  They  vary 
considerably  in  purity  of  colour,  and  are  marked  R,  B, 
2  B,  6  B,  etc.  The  redder  shades  are  known  by  such  com- 
mercial names  as  Serge  Blue,  Navy  Blue,  Blackley  Blue, 
etc.,  while  those  of  purer  tone  are  known  as  China  Blue, 
Night  Blue,  Soluble  Blue,  Water  Blue,  Cotton  Blue,  etc. 

Application  to  Cotton. — The  cotton  is  prepared  with 
tannic  acid  and  tartar  emetic,  and  dyed  at  60°-70°  C,  in 
a  separate  bath,  slightly  acidulated  with  alum. 


56    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Light  shades  of  blue  are  frequently  dyed  without  any 
previous  preparation. 

The  method  given  for  Spirit  Blue  may  also  be  used. 

Another  method  recommended  is  to  work  the  cotton 
at  60°  C.  in  a  bath  containing  the  colour  solution  and 
3  %  of  stannate  of  soda.  When  the  cotton  is  properly 
saturated,  acidify  the  solution  with  sulphuric  acid,  and 
work  i  hour  longer. 

In  all  cases  the  dye-bath  should  be  preserved,  since 
not  only  is  the  bath  never  completely  exhausted,  but 
further  lots  dyed  in  the  same  bath  have  also  a  brighter 
colour. 

Application  to  Wool. — Dye  as  in  the  same  manner  as 
with  Spirit  Blues. 

Application  to  Silk. — Dye  as  with  Spirit  Blues. 
Alkali  Blue. — This  is  a  special  kind  of  Soluble  Blue ; 
it  consists  essentially  of  the  sodium  salt  of  the  mono- 
sulphonic  acid  of  Rosaniline  Blue.  Both  red  and  blue 
shades  are  met  with ;  they  are  marked  accordingly  with 
r,  b,  etc.,  or  they  have  such  names  as  Guernsey  Blue,  Fast 
Blue,  Nicholson's  Blue,  etc.  The  red  shades  are  faster 
than  the  blue  shades,  both  to  light  and  to  the  action  of 
dilute  alkalis  in  milling,  etc. 

Alkali  Blues  are  not  applicable  in  cotton-dyeing. 
Application  to  Wool. — Wool  must  always  be  dyed  with 
Alkali  Blue  in  a  slightly  alkaline  bath  (hence  the  name). 
The  wool  takes  it  up  in  the  form  of  a  colourless  sodium 
salt.  The  development  of  the  colour — i.e.  the  precipita- 
tion on  the  fibre  of  the  blue-coloured  mono-sulphonic 
acid — is  effected  in  a  separate  and  slightly  acid  bath.  The 
water  of  the  dye-bath  should  be  as  free  from  lime-salts  as 
possible,  since  the  lime  compound  of  the  mono-sulphonic 
acid  is  insoluble. 

In  dyeing  wool,  add  to  the  dye-bath  the  amount  of 
colour  solution  requisite  to  obtain  the  desired  shade  (say 
0'5-5  %),  and  dissolve  in  it  also  4-8  %  of  carbonate  of 
soda  (crystals).  Introduce  the  wool  into  the  bath  at 
40°  C,  heat  rapidly  to  80°  or  100°  C,  and  boil  |-j  hour. 
It  is  then  taken  out,  washed  well  in  water,  and  transferred 
to  a  bath  containing  water  slightly  acidulated  with  sul- 
phuric acid  (5  %  of  sulphuric  acid,  168°  Tw.).  It  is 
worked  in  this  bath  for  15-20  minutes  at  60°  C.,  until  the 


ANILINE  COLOURING  MATTERS. 


57 


colour  is  fully  developed,  and  is  then  washed  free  from 
acid.  If  the  first  bath,  or  the  dye-bath,  as  it  may  be 
called,  is  sufficiently  alkaline,  the  wool  acquires  therein 
only  a  very  pale  bluish  tint,  but  on  passing  it  into  the 
second  bath,  which  may  be  named  the  acid  or  developing 
bath,  the  blue  is  at  once  developed.  The  dye-bath  is  never 
exhausted,  and  should  always  be  preserved.  For  succeeding 
lots  of  wool  add  proportionately  less  of  both  colour  solu- 
tion and  carbonate  of  soda.  Instead  of  carbonate  of  soda, 
borax  or  strong  ammonia  solution  may  be  used.  Under  no 
circumstances  whatever  should  the  sulphuric  acid  be  added 
to  the  dye-bath,  otherwise  the  colour-acid  will  be  precipi- 
tated. In  order  to  preserve  uniformity  of  dye  in  several 
lots  of  material,  it  is  very  advisable  not  to  develop 
different  shades  of  blue  in  the  same  acid-bath.  The  acid- 
bath  should  never  be  employed  at  a  temperature  above 
80°  C,  otherwise  the  blue  is  less  brilliant. 

In  order  to  match-off  any  given  shade,  a  small  sample 
of  the  woollen  material  must  occasionally  be  taken  from 
the  bulk  during  the  dyeing  operation,  and  passed  through 
warm  dilute  acid  to  develop  the  blue.  Only  in  this  way 
is  it  possible  to  regulate  what  amount  of  colour  solution 
should  be  added  to  the  dye-bath,  and  to  determine  the 
duration  of  the  dyeing  operation. 

Many  Alkali  Blues  are  not  improved  in  colouring 
power  by  an  addition  of  carbonate  of  soda  to  the  dye- 
bath  ;  they  seem  to  be  already  sufficiently  alkaline,  while 
others  give  even  inferior  colours  if  the  addition  is  made. 
In  all  cases  a  large  excess  of  alkaline  salt  is  to  be  avoided, 
since  it  tends  to  impoverish  the  colour. 

Colours  said  to  be  somewhat  faster  to  milling  are 
obtained  by  adding  zinc  sulphate  or  alum  to  the  acid-bath, 
since  these  salts  form  insoluble  lakes  with  the  colouring 
matter. 

Alkali  Blue  may  be  employed  for  the  purpose  of  ob- 
taining compound  colours,  by  using  it  in  conjunction  with 
various  acid-colours — e.g.  Crocein  Scarlet  or  Orange,  etc. 
In  these  cases  the  acid  bath  is  dispensed  with,  and  after 
dyeing  with  Alkali  Blue  and  washing,  the  wool  is  at  once 
worked  in  the  dye-bath  of  the  acid-colour,  with  the  neces- 
sary additions.  The  development  of  the  blue,  and  the 
dyeing  of  the  scarlet,  etc.,  are  thus  simultaneous. 


58    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Application  to  Silk. — Silk  is  dyed  like  wool,  but  it  is 
preferable  to  use  borax  in  the  dye-bath  instead  of  car- 
bonate of  soda  or  ammonia. 

(  C6H4-NH(C6H5) 
Rosaniline  Violets.    C  J  c'lf-CHs 

These  violets,  also  called  by  such  names  as  Phenyl  Violet, 
Spirit  Violet,  Parma  Violet,  Imperial  Violet,  etc.,  are 
hydrochlorides  of  mono-  and  di-phenyl-rosaniline.  They 
find  now  only  a  limited  use,  being  less  bright  than  the 
Methyl  Violets;  they  are,  however,  said  to  be  somewhat 
faster  to  light  and  to  milling,  and  may  be  used  with 
advantage  when  a  dull,  moderately-fast  violet  is  required, 
as  in  felt-hat  dyeing. 

Closely  related  to  Rosaniline  Violet  is  the  so-called 
Regina  Purple  (Brook,  Simpson,  and  Spiller). 

Application  to  Cotton. — Prepare  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  and  dye  in  a  bath  slightly 
acidulated  with  sulphuric  acid  or  alum. 

Application  to  Wool. — Dye  at  60°-80°  C.  in  a  colour 
solution  acidulated  with  4  %  of  sulphuric  acid,  168°  Tw. 
(Sp.  Gr.  1*84).  Since  these  are  basic  colouring  matters, 
the  need  of  acidulating  the  bath  is  noteworthy." 

Application  to  Silk. — Dye  at  60°-80°  C.  in  a  bath  con- 
taining boiled-off  liquor,  slightly  acidulated  with  sul- 
phuric acid. 

(  C6H4  NH-CH3 
Hofmann's  Violet.    C  )  n6S4'ni?'CH3 
(  NH:CH3C1 

This  colouring  matter,  also  called  Dahlia,  Primula,  etc., 
is  considered  as  the  hydrochloride  of  the  base  trimethyl- 
rosaniline;  it  is  only  used  for  red  shades  of  violet,  the 
bluish  violets  being  better  obtained  from  the  Methyl 
Violets.    The  colour  it  yields  is  not  fast  to  light. 

Application  to  Cotton. — Prepare  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  or  with  sulphated  oil  and 
aluminium  acetate ;  wash  and  dye  at  45°-50°  C.  in  a  neutral 
bath. 

Application  to  Wool.— Dye  at  60°-80°  C.  in  a  neutral 
bath,  or  with  the  addition  of  2-4  %  of  soap. 

Application  to  Silk.— Dye  at  50°-60°  C.  in  a  bath  con- 


ANILINE   COLOURING  MATTERS 


59 


taining  soap  or  "  boiled-off  "  liquor,  with  or  without  the 
addition  of  a  little  sulphuric  acid.  Wash  and  brighten 
in  a  bath  slightly  acidulated  with  acetic  or  tartaric  acid. 


This  colouring  matter,  also  called  Paris  Violet,  is  con- 
sidered as  the  hydrochloride  of  penta-methyl-para-ros- 
aniline.  Various  brands  are  sold — as  Methyl  Violet  R, 
B,  3  B,  etc. — according  as  they  yield  red  or  blue  shades 
of  violet. 

Some  of  the  Methyl  Violets  are  zinc  double  salts,  and 
are  then  sold  in  the  crystalline  state ;  with  these  the 
addition  of  soap  to  the  dye-bath  must  be  strictly  avoided. 

The  methods  of  applying  them  to  the  textile  fibres 
are  identical  with  those  employed  for  Hofmann's  Violet. 

Benzylr os aniline  Violet. — This  colouring  matter  is  the^ 
benzyl  (C7H7)  derivative  of  Methyl  Violet.  The  most 
highly  benzylated  product  is  generally  sold  as  Methyl 
Violet  6  B,  and  by  mixing  this  in  different  proportions 
with  Methyl  Violet  B,  the  various  marks  of  Methyl  Violet 
2  B,  3  B,  4  B,  5  B  are  obtained. 

Benzyl  Violet  yields  much  bluer  shades  of  violet  than 
Methyl  Violet,  although  the  method  of  its  application  to 
the  various  fibres  is  very  similar.  It  bears  the  addition 
of  a  little  sulphuric  acid  to  the  dye-bath  better  than 
Methyl  Violet. 

Alkali  Violet  (Meister,  Lucius  &  Briining)  is  applied  in 
the  same  manner  as  Alkali  Blue. 


This  colouring  matter  is  the  sodium  salt  of  di-methyl- 
rosaniline-tri-sulphonic  acid. 

Acid  Violet  5  RS  (basf)  is  the  corresponding  mono- 
methyl  compound. 

Acid  Violet  6  B  (basf)  is  the  corresponding  benzyl-  . 
methyl  compound. 

These  colouring  matters,  sold  by  several  manufacturers 
with  different  brands,  are  adapted  only  for  wool  and  silk, 


Methyl  Violet  C 


Acid  Violet  4  RS. 
(basf). 


(  OfiH.,(CH3)-NH(CHa)SO. 
)  C«Hg-NH(CHg)S03Na 

f  NH 


'3- 


60    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


and  are  applied  in  the  same  manner  as  Acid  Magenta. 
They  are  useful,  in  conjunction  with  other  acid  colouring 
matters,  for  producing  compound  shades. 

(  C6H4-N(CHa)2 
Methyl  Green.    C  0.^(0^)^-01 
(  NH-CH3-C1 

This  colouring  matter  may  be  regarded  as  the  methyl 
chloride  compound  of  Methyl  Violet.  It  occurs  in  com- 
merce in  the  crystalline  state  as  a  zinc  double  salt.  Al- 
though still  used,  it  has  been  very  largely  supplanted  by 
the  Acid  and  Benzaldehyde  Greens,  since  these  are  much 
cheaper,  and  offer  certain  advantages  in  point  of  applica- 
tion and  stability. 

Application  to  Cotton. — Dye  in  the  same  manner  as 
with  Benzaldehyde  Green. 

Application  to  Wool. — Owing  to  the  weak  attraction 
which  wool  has  for  Methyl  Green,  it  is  necessary  that  it 
should  be  mordanted  previous  to  being  dyed  with  this 
colouring  matter.  The  ordinary  mordants,  however,  are 
of  no  use,  and  recourse  is  had  to  the  singular  and  strong 
affinity  which  amorphous  sulphur  has  for  Methyl  Green. 

The  wool  is  mordanted  in  a  bath  containing  10-20  ■% 
of  thiosulphate  of  soda  (usually  called  hyposulphite  of 
soda)  and  acidified  with  5-10  %  of  sulphuric  acid,  168°  Tw. 
(Sp.  Gr.  1-84),  or  hydrochloric  acid,  32°  Tw.  (Sp.  Gr. 
1*16).  Introduce  the  wool  into  the  milky  liquid  at  40°  C, 
raise  the  temperature  gradually  to  80°  C.  in  the  course  of 
1  hour,  then  wash  well.  Dye  at  50°-60°  C.  in  a  separate 
bath  containing  Methyl  Green  and  2-4  %  of  borax  or 
acetate  of  soda. 

The  addition  of  these  latter  salts  to  the  dye-bath  has 
the  effect  of  neutralising  the  acid  remaining  in  the  wool 
after  washing;  if,  however,  previous  to  dyeing,  the  wool 
is  worked  for  about  \  hour,  at  70°  C,  in  a  weak  solution 
of  carbonate  of  soda  or  ammonia,  their  addition  to  the 
dye-bath  is  unnecessary. 

The  shade  produced  by  Methyl  Green  is  always  bluish, 
and  if  the  temperature  of  the  dye-bath  is  raised  to  100°  C. 
it  becomes  still  bluer,  owing  to  a  portion  of  the  colouring 
matter  decomposing  at  this  temperature  with  elimination 
of  methyl  chloride  and  the  production  of  Methyl  Violet; 


ANILINE   COLOURING  MATTERS. 


61 


the  effect  obtained  is  that  of  a  mixture  of  green  and  violet, 
namely,  blue  (Peacock  Blue).  If  it  is  desired  to  obtain 
yellower  shades  of  green,  Picric  Acid  may  be  added  to  the 
dye-bath,  but  since  this  only  dyes  in  an  acid-bath  (a  con- 
dition which  is  prejudicial  to  the  dyeing  property  of 
Methyl  Green)  one  must  add  also  a  small  proportion  of 
acetate  of  zinc.  This  salt  is  gradually  decomposed  by  the 
sulphur  already  fixed  on  the  wool,  and  the  liberated  acetic 
acid  causes  the  Picric  Acid  to  dye,  while  it  does  not  pre- 
vent the  Methyl  Green  from  doing  so.  The  zinc  sulphide 
produced  acts  as  a  mordant  for  the  Methyl  Green  in  the 
same  manner  as  the  sulphur.  Should,  however,  the  Methyl 
Green  dye  slowly,  from  over-acidity  of  the  bath,  the 
addition  of  a  little  acetate  of  soda  is  necessary. 

It  is  essential  that  in  the  operations  of  mordanting 
and  dyeing  the  use  of  metal,  either  in  the  dye-vessels 
themselves  or  in  the  utensils  employed,  should  be  strictly 
avoided,  otherwise  the  wool  may  acquire  a  dark  colour, 
or  be  spotted,  by  the  production  of  metallic  sulphides. 

Application  to  Silk. — Dye  exactly  as  in  the  case  of 
Benzaldehyde  Green. 

Auramine  (basf)  (Soc.  of  Chem.  Ind.,  Basle). 
[C6H4N(CH3)2]2  C  NH  HCL—  This  yellow  colouring  matter 
is  the  hydrochloride  of  tetra-methyl-diamido-benzo-phenom 
imide.  It  is  particularly  useful  to  the  cotton-dyer,  and  is 
said  to  resist  the  action  of  light  and  soap  solutions  fairly 
well,  but  is  readily  affected  by  chlorine.  It  should  be 
dissolved  in  hot  water,  but  the  solution  should  not  be 
boiled,  since  the  colouring  matter  is  thereby  decomposed. 
It  is  useful  for  producing  compound  shades  in  conjunc- 
tion with  other  basic  colouring  matters,  as  Safranine, 
Benzaldehyde  Green,  etc. 

Application  to  Cotton. — Mordant  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  and  dye  in  a  separate  bath. 
Introduce  the  cotton  into  the  cold  colour  solution,  and 
raise  the  temperature  of  the  bath  to  40°-50°  C. 

Application  to  Wool. — Dye  in  a  neutral  bath.  Enter 
cold  and  heat  gradually  to  70°  C.  Better  colours  are  said 
to  be  obtained  if  the  wool  is  previously  mordanted  with 
sulphur,  after  the  manner  in  vogue  for  Methyl  Green. 

Application  to  Silk. — Dye  in  the  same  manner  as  with 
Magenta. 


62    COLOURING  MATTERS  FOB  DYEING  TEXTILES. 


t  C6H4-N(C2H5)2 

Ethyl  Purple  6  B  (babf).    C    QgvN(  W2 

(  N(CH3)2C1 

This  colouring  matter  is  the  hydrochloride  of  hexa-ethyl- 
para-rosaniline.  It  is  applied  to  the  various  fibres  in  the 
same  way  as  Hofmann's  Violet. 

(  C6H4-N(CH3)2 

Crystal  Violet  5  BO  (basf).    C  ]  geg^CH^ 

(  N{CH3)2C1 

This  colouring  matter  is  the  hydrochloride  of  hexa-methyl- 
para-rosaniline.  It  is  applied  to  various  fibres  like  Hof- 
mann's  Violet,  over  which  it  possesses  the  advantage  of 
greater  colouring  power,  of  extreme  solubility  in  water, 
and  of  having  no  tendency  to  produce  a  bronze  scum  on  the 
surface  of  the  dye  liquor  or  on  the  dyed  material. 

(  06H4-N(CH3)2 
Victoria  Blue  4  R  (basf).    C  j  CioH6-N(CH3)(C6H5) 

( N6(ck8)aci 

This  colouring  matter  is  the  hydrochloride  of  penta- 
methyl-phenyl-triamido-diphenyLa-naphthyl-carbinol.  It 
is  applied  to  the  various  fibres  in  the  same  manner  as 
Hofmann's  Violet.  Wool  and  silk  may  be  dyed  with  the 
addition  of  a  little  acetic  or  sulphuric  acid  to  the  bath,  in 
the  same  manner  as  acid  colours.  The  dyeing  power  is 
thereby  somewhat  lessened  and  the  bath  is  not  so  well 
exhausted,  but  the  colour  obtained  seems  brighter. 

(  C6H4-N(CH8)3 
Victoria  Blue  B  (basf).    C  J  Cig6'NH-(C6H5) 

(  N(CH3)2C1 

This  is  the  tetra-methyl  compound  corresponding  to  Vic- 
toria Blue  4  R,  and  may  be  applied  in  the  same  way. 

Night  Blue  (basf). — This  colouring  matter  is  closely 
related  to  the  last,  and  is  applied  to  the  textile  fibres  in 
a  similar  manner.  It  requires  to  be  dissolved  in  dilute 
acetic  acid  to  prevent  decomposition  on  boiling. 

Phosphine  [C20H17N3'HC1]. — This  orange  colouring 
matter  (said  to  be  quinoline  derivative)  is  the  hydro- 


ANILINE  COLOURING  MATTERS. 


63 


chloride  of  the  base  chrysaniline.  Its  dyeing  properties 
are  similar  to  those  of  Magenta,  and  it  is  applied  to  the 
textile  fibres  in  the  same  manner. 

It  finds  only  a  limited  use  in  wool-  and  silk-dyeing, 
because  of  its  expense. 

Rosolane  [C27H24N9'HC1].—  This  colouring  matter  is  the 
hydrochloride  of  the  base  mauveine ;  it  is,  indeed,  the 
original  Perkin's  Violet. 

Its  method  of  application  is  similar  to  that  of  the 
Methyl  Violets.  Although  itself  not  requiring  a  mordant, 
it  may  be  used  in  conjunction  with  polygenetic  colouring 
matters  for  the  production  of  compound  shades.  It  is 
used  as  a  substitute  for  Orchil  or  Ammoniacal  Cochineal 
in  the  production  of  bright  greys. 

(b.)  Induline  and  Safranine  Group. 

Indulines. — These  comprise  a  number  of  colouring 
matters  made  by  different  processes,  but  all  possessing 
somewhat  similar  dyeing  properties.  They  are  known  by 
a  variety  of  commercial  names,  e.g.  Violaniline,  Nigrosine, 
Elberfeld  Blue,  Bengaline,  Aniline  Grey,  Coupier's  Blue, 
Roubaix  Blue,  etc. 

Those  used  for  cotton-dyeing  are  insoluble  in  water, 
and  require  to  be  dissolved  in  methylated  spirit.  These 
Spirit  Indulines  are  hydrochlorides  of  a  colour-b  ase,  as 
violaniline,  triphenyl-violaniline,  etc.  For  wool-  and  silk- 
dyeing  they  are  treated  with  strong  sulphuric  acid;  they 
are  thus  rendered  soluble  in  water,  and  are  sold  as 
sodium  salts  of  the  corresponding  sulphonic  acids. 

They  all  yield  dark,  dull  blue  colours,  not  unlike 
indigo-vat  blues,  to  imitate  which  they  are  frequently 
employed. 

Application  to  Cotton. — Prepare  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  wash,  and  dye  in  a  separate 
bath  containing  the  colour  solution,  acidified  slightly  with 
sulphuric  acid  or  by  the  addition  of  alum  (10  %).  Dye 
at  a  temperature  of  about  60°  C.  The  bath  is  not  ex- 
hausted, and  must  be  preserved  for  succeeding  lots  of 
material.    One  may  also  employ  the  indigo-vat  method. 

Application  to  Wool. — Owing  to  the  precipitation  of 
the  free  sulphonic  acids  of  these  colours  on  the  addition 
of  acid  to  their  solutions,  it  is  extremely  difficult  to  dye 


6 A    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


light  shades  evenly  with  them.  They  are  best  adapted 
for  dyeing  dark  shades. 

Add  the  requisite  amount  of  colour-solution  (5-15  %) 
to  the  dye-bath,  heat  to  100°  C.  as  rapidly  as  possible, 
enter  the  wool,  and  boil  hour,  without  any  other 

addition.  Continue  now  to  boil  1  hour  longer,  during 
which  period  add  from  time  to  time  dilute  sulphuric 
acid  in  small  portions.  Use  5-15  %  of  sulphuric  acid, 
168°  Tw.  (Sp.  Gr.  184),  according  to  the  amount  of  colour- 
ing matter  employed. 

The  long  boiling  with  colour  solution  alone  enables 
the  wool  to  become  thoroughly  permeated  with  the  colour- 
ing matter  while  still  in  the  soluble  state.  An  addition 
of  5-10  %  of  borax,  carbonate  of  soda,  or  strong  ammonia 
solution  at  this  stage  is  beneficial.  The  actual  dyeing 
of  the  wool  begins  only  when  the  bath  is  acidulated;  the 
addition  of  acid  should  always  be  made  slowly,  so  that 
the  wool  may  take  up  the  gradually  precipitated  colouring 
matter  as  evenly  as  possible. 

Wool  is  said  to  dye  much  better  with  Induline  if  it 
has  been  previously  rinsed  in  a  weak  solution  of  bleaching- 
powder  and  then  in  dilute  hydrochloric  acid. 

These  colours  have  been  frequently  recommended  as 
good  substitutes  for  indigo-vat  blues.  Although  fairly 
fast  to  light,  they  gradually  lose  their  bluish  tint  and 
brilliancy  on  exposure,  and  assume  a  dull  greyish  tone. 
Towards  weak  alkalis  they  are  moderately  fast ;  the  action 
of  acids  they  withstand  perfectly.  In  conjunction  with 
other  acid-colours  they  are  useful  for  producing  a  large 
variety  of  compound  shades. 

Application  to  Silk. — Dye  in  a  bath  containing 
"  boiled-off"  liquor,  acidified  slightly  with  sulphuric  acid. 
Enter  the  silk  at  60°  C,  add  the  colour  solution  gradually, 
raise  the  temperature  gradually  to  100°  C,  and  boil  J  hour. 
Wash  and  brighten  with  dilute  sulphuric  acid. 

Naphthalene  Pink  [C30H21N3-HC1  +  H20].—  This 
colouring  matter,  also  called  Magdala  Red,  and  derived 
from  amido-azo-naphthalene,  is  the  hydrochloride  of  the 
base  rosa-naphthylamine.  It  is  but  little  used,  namely, 
for  the  purpose  of  obtaining  on  silk  bright  pinks,  which 
have  a  strong  yellowish-red  fluorescence. 

Application    to    Silk. — Dye    in    a    bath  containing 


ANILINE   COLOURING  MATTERS. 


65 


"  boiled-off  "  liquor,  with  or  without  the  addition  of  sul- 
phuric acid.  Brighten  with  dilute  sulphuric  or  tartaric 
acid.  The  colour  is  faster  than  that  given  by  Magenta, 
Eosin,  or  Safranine;  it  is  fast  to  dilute  acids  and  alkalis, 
but  not  to  light. 

Safranine  [C21H22N4*HC1]. — In  chemical  constitution 
this  red  colouring  matter  is  apparently  allied  to  Magenta, 
and  is  the  hydrochloride  of  a  colour-base  safranine.  It  is 
applied  to  the  various  fibres  in  the  same  manner  as 
Magenta.  On  wool  the  colour  is  not  fast  to  light.  Strictly 
speaking,  the  name  Safranine  is  given  to  several  closely- 
allied  products.  Fuchsia  (Soc.  Ch.  Ind.,  Basle)  is 
dimethyl-aniline-safranine. 

Application  to  Cotton. — Prepare  the  cotton  with  tannic 
acid  and  tartar  emetic,  wash  and  dye  in  a  neutral  bath 
at  50°  C.  One  may  also  steep  the  cotton  in  a  solution 
of  lead  acetate  (with  or  without  previous  impregnation 
with  a  solution  of  soap),  dry,  and  dye  in  a  neutral  bath 
of  the  colouring  matter ;  the  colour  thus  obtained  is 
objectionable  because  of  the  lead  it  contains.  Fixed  with 
tannic  acid  and  tartar  emetic  the  colour  is  fairly  fast  to 
light. 

Application  to  Wool  and  Silk. — Dye  in  the  same 
manner  as  with  Magenta. 

Neutral  Red  (L.  Casella  &  Co.). — This  colouring 
matter  and  others  called  Neutral  Blue  and  Neutral  Violet, 
being  allied  to  Safranine,  are  all  applied  to  the  various 
textile  fibres  by  similar  methods.  They  yield  dull  shades 
of  red,  blue,  and  violet  respectively,  not  fast  to  light  on 
wool.  They  are  of  little  use  in  wool-  and  silk-dyeing, 
but  may  be  used  with  advantage  by  the  cotton-dyer  for 
producing  compound  shades. 

New  Blue  D  (Casella  &  Co.).— This  colouring  matter 
gives  a  colour  closely  resembling  that  of  vat-indigo  blue, 
which  on  cotton  is  extremely  fast  to  light.  Although 
affected  by  alkalis,  it  is  well  adapted  for  cotton-dyeing, 
and  may  in  many  cases  replace  vat-indigo  blue.  New 
Blue  D  is  frequently  used  in  conjunction  with  Methylene 
Blue  or  other  basic  colouring  matters, 

Application  to  Cotton. — Mordant  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  and  dye  in  a  neutral  bath  of 
the  colour  solution. 
E 


66    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


(c.)  Aniline  Black  Group. 

Aniline  Black.  —  Unlike  other  colouring  matters, 
Aniline  Black  is  not  a  commercial  article.  For  the  pur- 
pose of  the  dyer  it  must  be  produced  upon  the  fibre  itself. 
Little  or  nothing  is  known  of  its  chemical  constitution. 
It  is  a  product  of  the  oxidation  of  a  salt  of  aniline,  gener- 
ally analine  hydrochloride,  and  appears  to  exist  in  two 
states  of  oxidation.  The  less  oxidised  product  is  a  blue- 
black,  somewhat  sensitive  to  the  action  of  acids,  particu- 
larly sulphurous  acid,  under  the  influence  of  which  it 
acquires  a  greenish  tint.  The  original  colour  can  only  be 
temporarily  restored  by  treatment  with  an  alkaline  solu- 
tion. The  more  Highly  oxidised  product  is  a  violet-toned 
black,  which  is  not  turned  green  by  acids.  This  is  pro- 
duced by  submitting  the  former  to  a  supplementary  oxida- 
tion. It  is  remarkable  for  its  extreme  fastness  to  acids, 
alkalis,  light,  etc.,  and  is  indeed  one  of  the  most  perma- 
nent dyes  known. 

Application  to  Cotton. — For  dyeing  cotton  Aniline 
Black  the  most  usual  oxidising  agent  employed  is  bichro- 
mate of  potash  or  chromic  acid.  According  to  the  tem- 
perature at  which  the  dyeing  is  effected,  two  methods  may  be 
distinguished,  namely,  the  warm  method  and  the  cold  method. 

Warm  Method.— For  100  kg.  =  220  4  lb.  of  cotton  the 
dye-bath  contains  the  following  ingredients  :  1,600  litres 
=  352  gallons  water,  40  kg.  =  88*1  lb.  of  hydrochloric  acid, 
34°  Tw.  (Sp.  Gr.  riV),  10  kg.  =  22'0  lb.  of  aniline,  10-14 
kg.  —  22'0-30*8  lb.  of  bichromate  of  potash. 

These  proportions  may  be  varied  according  to  the 
particular  shade  of  black  required.  A  portion  of  the 
hydrochloric  acid  may  also  be  replaced  by  an  equivalent 
amount  of  sulphuric  acid.  Use,  for  example,  24  kg.  = 
52  8  lb.  of  hydrochloric  acid,  and  4-6  kg.  =  8-8-13*2  lb.  of 
sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84).  The  intensity  of 
the  colour,  however,  is  always  regulated  by  the  amount  of 
aniline  employed. 

The  aniline  and  hydrochloric  acid,  diluted  slightly  with 
water,  are  carefully  mixed  in  a  suitable  glazed  earthen- 
ware vessel,  and  the  acid  solution  of  aniline  hydrochloride 
thus  obtained  is  added  to  the  dye-bath  previously  filled 
with  cold  water.  The  bichromate  of  potash  is  dissolved 
separately  in  a  little  warm  water  and  added  to  the  bath. 


ANILINE   COLOURING  MATTERS. 


^7 


The  cotton  is  worked  for  1  hour  in  the  cold  solution, 
until,  indeed,  it  has  acquired  a  considerable  intensity  of 
colour,  after  which  the  temperature  is  gradually  raised  to 
50°-60°  C.    The  whole  operation  may  last  from  1-3  hours. 

Another  method  is  as  follows  :  Dye  the  cotton  in  the 
cold  for  1  hour  with  only  half  the  quantity  of  the  severa] 
ingredients  added  to  the  bath,  then  add  the  remainder, 
and  continue  the  dyeing  in  the  cold  for  1  hour  longer ; 


Fig.  5. — Aniline  Black  Dyeing  Machine. 

after  this  raise  the  temperature  gradually  to  50°-60°  C, 
and  continue  the  dyeing  for  another  hour. 

The  more  concentrated  the  solution  and  the  greater  its- 
acidity,  the  more  rapidly  does  the  dyeing  take  place. 
Excess  of  acid  and  prolonged  heating  tend  to  give  bronze- 
coloured  blacks,  and  much  of  the  colouring  matter  is  only 
superficially  fixed.  If,  however,  the  heating  has  been  of 
short  duration,  the  black  has  a  bluish  tone,  and  is  liable 
to  become  green  under  the  influence  of  acids. 


68    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


It  is  essential  that  the  temperature  of  the  bath  should 
be  raised  very  gradually,  otherwise  there  is  a  great  loss  of 
colouring  matter,  since  much  of  it  is  then  precipitated  in 
the  bath  and  not  on  the  fibre. 

After  dyeing,  the  cotton  must  be  well  washed  with 
water,  then  boiled  in  a  solution  of  soap  containing  5-10  g. 
=  77'1-154'3  grains  per  litre  =  1  quart,  with  or  without 
the  addition  of  a  little  carbonate  of  soda,  and  finally 
dried. 

Cold  Method. — According  to  this  method  the  dyeing 
operation  is  conducted  entirely  in  the  cold,  the  propor- 
tions of  the  ingredients  and  the  concentration  of  the  bath 
being  altered  to  render  this  possible. 

For  100  kg.  =  2204  lb.  of  cotton  use  16-20  kg.  = 
35*2-14  0  lb,  of  hydrochloric  acid,  20  kg.  =  44*0  lb.  of  sul- 
phuric acid,  8-10  kg.  =  17-6-22  0  lb.  of  aniline,  14-20  kg.  === 
30'8-44-0  lb.  of  bichromate  of  potash,  10  kg.  =  22'0  lb.  of 
ferrous  sulphate.  The  quantity  of  water  should  be  very 
much  smaller  than  in  the  warm  method,  otherwise  the 
dyeing  would  either  be  incomplete  or  would  take  too  long. 
Fig.  5  represents  an  apparatus  for  dyeing  cotton  yarn 
Aniline  Black.  It  is  specially  designed  so  that  the 
hanks  can  be  properly  manipulated  in  as  little  liquid  as 
possible.  It  consists  of  a  strong  wooden  dye-bath,  about 
2  m.  =  6j  feet  long,  and  longitudinally  divided  into  two 
compartments,  each  with  rounded  bottom.  Above  are  two 
corresponding  square  rollers,  each  capable  of  holding 
about  5  kg.  =  11  lb.  of  cotton  yarn;  there  is  also  a  sup- 
port with  two  arms,  on  which  the  rollers  can  be  placed 
either  at  the  end  of  the  dyeing  process  or  for  the  purpose 
of  filling  them  with  yarn  before  beginning.  Several  such 
dye-baths  are  arranged  in  line,  the  rollers  being  turned 
by  power,  alternately  to  right  and  left,  in  order  to  avoid 
entanglement  of  the  hanks.  The  use  of  such  a  machine 
saves  labour,  prevents  the  corrosion  of  the  workmen's 
hands  by  the  chromic  acid,  and  gives  a  more  regularly 
oxidised  black. 

It  will  be  noticed  that  the  proportions  of  bichromate 
of  potash  and  acid  employed  in  the  cold  method  are  larger 
than  in  the  warm  method ;  this  is  in  order  to  facilitate 
the  oxidation  of  the  aniline  salt  at  the  lower  temperature. 
The  addition  of  the  sulphuric  acid  has  a  similar  effect,  but 


ANILINE   COLOURING  MATTERS.  69 


it  also  tends  to  yield  ultimately  a  more  pleasing  tone  of 
black.  The  use  of  hydrochloric  acid  produces  blue-blacks, 
while  sulphuric  acid  alone  gives  such  as  are  of  a  reddish 
hue.  The  addition  of  the  ferrous  sulphate  is  for  the  pur- 
pose of  rendering  the  black  less  liable  to  turn  green ;  of 
course,  in  the  bath  it  is  changed  to  ferric  sulphate,  and 
this  acts  as  an  oxidising  agent. 

The  method  of  preparing  the  dye-bath  for  the  cold 
method  is  similar  to  that  already  described.  The  aniline 
hydrochloride  is  previously  made  by  mixing  the  aniline 
and  hydrochloric  acid ;  separate  solutions  of  the  ferrous 
sulphate,  bichromate  of  potash,  and  sulphuric  acid  are 
also  kept  in  readiness.  The  cotton  is  first  worked  for 
about  1  hour  with  only  half  the  full  amount  of  the  several 
ingredients  in  the  bath.  At  the  end  of  this  time,  when 
the  cotton  has  already  acquired  quite  a  black  colour, 
it  is  lifted  out,  the  other  half  of  the  ingredients  is  added, 
the  cotton  is  then  re-entered,  and  the  dyeing  is  continued 
1-lJ  hour  longer. 

After  dyeing,  the  cotton  is  well  washed  and  boiled 
with  a  solution  of  soap  and  carbonate  of  soda,  as  previ- 
ously stated,  and  dried.  The  use  of  soap  alone  gives 
violet-toned  blacks ;  the  addition  of  carbonate  of  soda 
makes  the  shade  bluer. 

Although  the  black  produced  by  either  of  the  above 
methods,  but  especially  by  the  cold  method,  is  tolerably 
stable,  it  is  necessary,  in  order  to  render  it  perfectly 
ungreenable,  to  submit  the  dyed  cotton,  after  washing, 
to  a  supplementary  oxidation.  Several  methods  have  been 
proposed  for  this  purpose,  but  perhaps  the  following,  in 
which  ferric  sulphate  is  the  oxidising  agent,  is  the  most 
serviceable  :  Prepare  a  mixture  of  20  kg.  —  44  0  lb.  of 
ferrous  sulphate,  5  kg.  =  11  lb.  of  bichromate  of  potash, 
15-18  litres  =  33'0-39'6  lb.  of  sulphuric  acid,  168°  Tw., 
60-70  litres  =  13'2-15'4  gals,  of  water.  Add  5  litres  = 
1*1  lb.  of  this  mixture  to  500  litres  =  HO'O  lb.  of  water, 
and  work  the  cotton  in  the  solution  for  §  hour  at  75°  C.  ; 
then  wash  well,  boil  with  soap,  and  dry. 

Other  Methods.—  Another  method,  depending  for  its 
efficacy  upon  the  optical  effect  that  a  mixture  of  violet 
and  green  appears  blue,  is  to  dye  the  black  in  a  weak 
solution  of  Methyl  Violet.    This  violet  is  fixed,  it  is  sup- 


70    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


posed,  by  reason  of  the  cotton  itself  having  been  partially 
oxidised  and  changed  into  oxycellulose  during  the  dyeing 
process. 

Two  other  methods  of  producing  Aniline  Black  on 
cotton,  though  not  practically  employed,  possess  sufficient 
interest  to  deserve  mention.  One  is  that  borrowed  from 
the  method  so  successful  in  the  printing  of  calico  with 
Aniline  Black.  It  is  based  upon  oxidising  the  aniline 
salt  by  means  of  potassium  chlorate  in  the  presence  of 
vanadium.  The  cotton  is  impregnated  with  a  somewhat 
concentrated  solution  containing  5-20  %  of  aniline  hydro- 
chloride (according  to  the  intensity  and  fastness  of  the 
black  required),  2-10  %  of  potassium  chlorate,  and  a 
very  minute  quantity  of  vanadium  chloride  (not  more 
than  3^  of  the  weight  of  aniline  hydrochloride  employed). 
After  wringing  out  the  excess  of  liquid,  the  colour  is  de- 
veloped by  hanging  the  cotton  in  an  ageing  stove  heated  to 
25°-30°  C,  and  in  which  the  air  is  kept  slightly  moist 
by  admitting  a  little  steam.  The  chief  defect  of  this 
process  is  that  an  uneven  colour  is  liable  to  be  produced, 
since  the  oxidation  will  take  place  unequally  if  there  is  a 
partial  drying  of  the  fibres,  or  an  unequal  exposure  of 
the  fibres  to  the  air. 

The  other  method  referred  to  is  that  proposed  by  Gop- 
pelsroeder,  in  which  a  vat  of  reduced  Aniline  Black  is 
made,  the  cotton  being  dyed  in  it  just  as  in  an  indigo-vat. 

The  Aniline  Black  is  first  prepared  separately,  namely, 
by  heating  a  solution  containing  aniline  hydrochloride, 
potassium  chlorate,  ammonium  chloride,  and  copper  sul- 
phate. The  black  pigment  thus  produced  is  purified  by 
boiling  with  water,  and  afterwards  with  alcohol.  It  is 
then  heated  with  a  solution  of  caustic  potash,  and  the 
colour-base  of  the  black  thus  liberated  is  washed,  dried, 
and  dissolved  in  fuming  sulphuric  acid.  This  solution  is 
poured  into  cold  water,  and  the  greenish-black  precipitate 
thus  produced  is  dissolved  in  caustic  alkali,  and  reduced 
by  heating  with  the  addition  of  glucose,  hydrosulphite 
of  soda,  or  zinc  powder.  Jberrous  sulphate  and  lime  are 
inoperative.  If  cotton  be  steeped  in  the  brownish-yellow 
solution  thus  obtained,  and  then  exposed  to  the  air, 
it  acquires  gradually  a  blue  colour.  By  submitting  this 
colour  to  a  supplementary  oxidation  it  changes  to  a  light 


ANILINE   COLOURING  MATTERS. 


71 


grey  or  deep  black,  according  to  the  concentration  of  the 
vat.  A  judicious  combination  of  the  aniline  black  vat 
with  an  indigo-vat  may  yield  very  fast  deep  blues. 

Application  to  Wool  and  Silk.—  These  fibres,  especially 
the  former,  cannot  be  dyed  satisfactorily  with  Aniline 
Black.  It  would  appear  as  if  the  reducing  action  of  the 
fibres  themselves  hindered  the  oxidation  of  the  aniline  salt. 
Better  results  are  said  to  be  obtained  if  the  fibres  are 
previously  oxidised  by  immersing  them  for  some  time 
either  in  a  weak  solution  of  permanganate  of  potash, 
or  in  a  dilute  solution  of  bleaching-powder  to  which 
hydrochloric  acid  has  been  added.  After  this  preliminary 
process,  the  wool  or  silk  is  washed  and  dyed  by  a  process 
exactly  analogous  to  the  one  described  for  dyeing  cotton. 

N  aphthyl  amine  Violet. — This  colouring  matter,  derived 
from  naphthylamine  hydrochloride  in  a  manner  similar 
to  that  by  which  Aniline  Black  is  obtained,  must  also  be 
produced  upon  the  fibre  itself. 

(d.)  Aniline  Colours  Containing  Sulphur. 

Aldehyde  Green  [C22H27N3S20]. — This  colouring  matter, 
now  seldom  used,  is  invariably  prepared  by  the  dyer  him- 
self, by  the  action  of  aldehyde  upon  a  solution  of  Magenta 
dissolved  in  strong  sulphuric  acid. 

(  C6H3-]Sr(CH3)2 
Methylene  Blue.    N  >S' 

I   (  C6H3'N(CH3)2-C1 
i  i 

Methylene  Blue,  a  derivative  of  dimethyl-aniline,  gives 
a  greenish  blue. 

Application  to  Cotton. — The  cotton  is  prepared  with 
tannic  acid  and  tartar  emetic,  then  washed  and  dyed  in 
a  separate  bath  containing  Methylene  Blue  solution.  The 
addition  to  the  dye-bath  of  a  small  quantity  of  carbonate 
of  soda  or  ammonia  is  beneficial.  Enter  the  cotton  cold, 
and  raise  the  temperature  gradually  to  100°  C. 

Application  to  Wool. — Add  to  the  dye-bath  the  requisite 
amount  of  colour  in  solution  (0'5-5  %)  and  1-2  %  of  car- 
bonate of  soda  (crystals)  or  ammonia.  Enter  the  wool 
cold,  and  raise  the  temperature  gradually  to  100°  C.  in 
the  course  of  \  hour,  and  boil  i  hour  longer. 

Ethylene  Blue  (from  diethyl-aniline)  resembles  Methy- 
lene Blue. 


72 


CHAPTER  V. 

QUINOLINE  AND  PHENOL  COLOURING  MATTERS. 

Flava?iiline  (Meister,  Lucius,  and  Bruning) 
[C9H5N(CH3)C6H4(NH2)HC1]. 
This  basic  yellow  colouring  matter,  derived  from  ace- 
tanilide,  is  the  hydrochloride  of  the  quinoline  base 
flavaniline.  It  is  applied  to  cotton,  wool,  and  silk,  in  the 
same  manner  as  Magenta.  On  wool  the  colour  is  de- 
veloped a  little  by  passing  the  dyed  material  through 
dilute  sulphuric  acid.  Brighter  colours  are  obtained  on 
wool  mordanted  with  thiosulphate  of  soda  according  to 
the  method  employed  when  dyeing  with  Methyl  Green. 
Flavaniline  yellow  is  not  fast  to  light. 

Flavaniline  S  is  an  alkali  salt  of  the  sulphonic  acid  of 
the  flavaniline  base.  It  is  applied  to  wool  and  silk  in 
an  acid  bath. 

Quinoline  Blue  [C28H35N2I]. — This  disused  colouring 
matter,  also  called  Cyanine,  is  applied  to  cotton,  wool, 
and  silk  in  the  same  manner  as  Magenta.  The  colours  it 
yields  are  very  fugitive  towards  light. 

Quinoline  Yellow  (Berlin  Aniline  Co). — This  colour- 
ing matter  is  the  sodium  salt  of  the  sulphonic  acid  of 
quinoline-phthalein.  It  gives  a  pure  yellow  colour,  and 
is  applied  in  an  acid  dye-bath  in  the  same  manner  as 
other  sulphonic  acid  colouring  matters. 

(a.)  Nitro  Compounds  of  Phenol. 

Picric  Acid  [CrH2(N02)3*OH].— This  colouring  matter 
is  tri-nitro-phenol ;  it  is  used  only  in  silk-  and  wool- 
dyeing.  Cotton  has  no  attraction  for  it,  and  although 
it  may  be  fixed  on  this  fibre  by  means  of  albumen,  the 
method  has  no  practical  value.  The  animal  fibres,  on  the 
contrary,  readily  take  up  Picric  Acid  from  an  acid  solu- 
tion. It  gives  a  clear  bright  yellow,  free  from  any  tinge  of 
orange;  indeed,  when  compared  with  most  other  yellows, 
it  appears  to  have  a  greenish  hue. 

Application  to  Wool.—Dye  for  |-1  hour,  at  60°-100°  C, 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  73 


with  1-4  %  of  Picric  Acid,  with  the  addition  of  2-4  % 
of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1'84).  The  bath  must 
be  preserved,  since  it  cannot  be  exhausted. 

By  repeated  washing  with  water  only  is  it  possible 
to  remove  nearly  the  whole  of  the  colour  from  the  dyed 
fibre.  It  does  not  stand  milling  well,  both  on  this  account 
and  because  the  colour  becomes  brownish  under  the  in- 
fluence of  alkalis. 

It  is  also  not  a  good  dye  for  the  woollen  part  of  mixed 
goods  (wool  and  cotton),  since  it  comes  off  in  the  tannin 
bath  used  for  preparing  the  cotton.  It  is  frequently  em- 
ployed for  the  production  of  compound  colours,  e.g.  with 
Methyl  Green  and  with  Indigo  Carmine  for  yellowish 
greens,  with  Acid  Violet  for  olive,  etc. 

A  noteworthy  feature  of  Picric  Acid  yellow  is  that  on 
exposure  to  light  it  rapidly  becomes  darker,  acquiring  a 
dull  orange  colour,  which  does  not  readily  fade. 

Application  to  Silk. — Dye  with  0*5-1  %  of  Picric  Acid 
in  a  bath  slightly  acidified  with  sulphuric  acid,  with  or 
without  the  addition  of  "  boiled-off  "  liquor.  The  colour 
marks  off  on  paper,  if  submitted  to  pressure  for  some 
time.  The  compound  colours  dyed  with  Picric  Acid  and 
Methyl  Violet  are  fluorescent. 

The  method  of  dyeing  a  weighted  yellow  on  silk  by 
first  preparing  the  fibre  with  lead  acetate,  and  then  dyeing 
with  Picric  Acid,  is  not  to  be  recommended,  since  the 
colour  blackens  in  the  presence  of  sulphuretted  hydrogen, 
and  the  picrate  of  lead  causes  the  silk,  when  ignited,  to 
burn  like  touch-paper. 

Phenyl  Brown. — This  colouring  matter,  which  consists 
of  a  mixture  of  dinitrophenol  CrH3(N02)2'OH  with  an 
amorphous  brown  substance,  is  not  now  used  in  dyeing 
to  any  very  large  extent.    It  is  not  applicable  to  cotton. 

Application  to  Wool. — It  gives  nice  brown  shades, 
which  are  said  to  be  very  fast  to  light. 

Dye  in  a  bath  slightly  acidified  with  sulphuric  acid. 
If  the  wool  is  boiled  with  bichromate  of  potash  after  dye- 
ing, the  colour  assumes  a  redder  tone. 

Application  to  Silk. — Dye  in  a  bath  slightly  acidified 
with  sulphuric  acid. 

Victoria  Yellow  [06H2(0Hs)(NO2),"OK].- This  colour- 
ing matter  is  the  potassium  salt  of  dinitro-p-cresol.  The 


74    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


dyes  it  yields  are  so  very  fugitive  that  it  is  now  no  longer 
employed.  It  is  applied  to  wool  and  silk  in  the  same  way 
as  Picric  Acid. 

Campobello  Yellotu  [C10H6(NO2)'ONa]. — This  colouring 
matter  is  the  sodium  salt  of  a-nitro-a-naphthol ;  it  was 
formerly  also  sold  as  French  Yellow  and  Chryseinic  Acid. 
It  is  applied  in  the  same  way  as  Naphthol  Yellow,  and 
gives  similar  shades.  It  is  applicable  only  to  silk  and 
wool,  but  the  colour  is  neither  fast  to  light  nor  to  washing. 

Naphthol  Yellow  [C10H5(NO2)2-ONa  +  H20].— This 
colouring  matter  is  the  sodium  or  calcium  salt  of  dinitro-a- 
naphthol ;  it  is  also  known  by  the  following  names  :  Mar- 
tius  Yellow,  Manchester  Yellow,  Golden  Yellow,  Saffron 
Yellow,  Primrose,  Naphthaline  Yellow,  etc.  It  is  ap- 
plicable only  to  silk  and  wool,  but,  since  it  is  volatile 
even  at  low  temperatures,  it  has  the  defect  of  marking  off. 

Application  to  Wool. — Dye  in  an  acid  bath  for  1  hour 
with  0'5-3  %  of  colouring  matter  and  3-6  %  of  sulphuric 
acid,  168°  Tw.  (Sp.  Gr.  1*84).  Enter  the  wool  at  40°  C, 
and  heat  gradually  to  100°  C.  If  desirable,  one  may  also 
acidify  with  5-10  %  of  alum  instead  of  sulphuric  acid. 
According  to  the  amount  of  colouring  matter  employed, 
the  colour  varies  from  a  pale  lemon-yellow  to  a  deep  and 
brilliant  orange-yellow.  It  is  not  fast  to  light,  and  is  not 
suitable  for  goods  which  have  to  be  milled. 

Application  to  Silk. — It  is  applied  in  the  same  manner 
as  Picric  Acid. 

Naphthol  Yellow  S  (basf)  [C10H/(NO2)2'ONa-SO3Na]. 
— This  colouring  matter  is  the  sodium  salt  of  the  sulphonic 
acfd  of  Naphthol  Yellow;  it  is  used  only  in  silk-  and 
wool-dyeing.  It  is  very  much  faster  to  washing  than 
either  Picric  Acid  or  Naphthol  Yellow.  It  is  not  volatile 
on  steaming,  and  does  not  mark  off,  but  is  fugitive  to 
light.    It  is  applied  in  the  same  way  as  Naphthol  Yellow. 

New  Yellow  (Bayer  &  Co.)  [C10H5NO2OKSO3K]  is  the 
potassium  salt  of  the  nitro  derivative  of  /3-naphthol-a- 
monosulphonic  acid. 

Application  to  Wool. — The  method  of  dyeing  is  the 
same  as  with  Naphthol  Yellow,  and  similar  shades  are 
produced.  The  colour  is  not  fast  to  light.  The  addition 
of  a  simall  percentage  of  stannic  chloride  to  the  dye-bath 
adds  brilliancy  to  the  colour. 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  75 


Application  to  Silk. — Dye  in  a  bath  slightly  acidified 
with  sulphuric  acid,  and  without  the  addition  of  "  boiled- 
off  n  liquor  or  soap. 

Palatine  Orange  (basf)  [C12H4(N02)4(ONH4)2]  — This 
colouring  matter  is  the  ammonium  salt  of  tetra-nitro-y- 
diphenol.  It  is  applied  to  wool  and  silk  in  a  bath  acidu- 
lated with  sulphuric  or  acetic  acid. 

Heliochrysin  [C10H3(NO2)4ONa]. — This  colouring  mat- 
ter is  the  sodium  salt  of  tetra-nitro-naphthol ;  it  is  also 
known  as  Sun  Gold.  It  gives  fine  orange  shades  on  wool 
and  silk,  but  it  is  not  fast  to  light,  and  has  been  little 
employed  in  practice. 

Aurantia  [N(C6H2(N02)3)2NHJ.— This  orange  colour- 
matter  is  the  ammonium  salt  of  hexa-nitro-diphenyl- 
amine ;  it  is  also  known  as  Imperial  Yellow,  and  is  only 
applicable  to  wool  and  silk. 

Dye  in  a  bath  very  slightly  acidified  with  sulphuric 
acid.  Contact  of  the  solution  with  metallic  surfaces  must 
be  avoided,  since  these  render  the  solution  brown.  Only 
glass  or  wooden  vessels  should  be  employed  for  dissolving 
or  dyeing.  It  has  been  stated  that  Aurantia  has  decidedly 
poisonous  properties,  and  occasions  skin  eruptions. 

(b.)  Colouring  Matters  produced  by  the  Action  of  Nitrous 
Acid  on  Phenols. 

Resorcin  Blue  [C18H3(NH4)Br6N2OJ(  ?).—  This  colour- 
ing matter,  also  known  as  Fluorescent  Blue,  is  the  am- 
monium salt  of  hexa-brom-diazo-resorufin.  It  is  applicable 
to  wool  and  silk  only,  more  particularly  the  latter. 

Silk  dyed  with  this  colour  is  remarkable  for  its  reddish 
fluorescence,  the  red  colour  appearing  very  prominently 
by  gas-light.  It  is  said  to  be  fast  to  light,  washing,  and 
acids.  When  used  in  combination  with  other  colouring 
matters  it  gives  pleasing  shades,  all  possessing  fluorescence. 

Application  to  Silk. — Dye  in  a  bath  containing 
"  boiled-off  "  liquor  or  soap,  and  neutralised  with  acetic 
acid.  Brighten  in  a  cold  bath  slightly  acidified  with  tar- 
taric or  sulphuric  acid. 

Naphthol  Green  (L.  Casella  &  Co.)  [C10H5O7SNFe](  ?). 
— This  colouring  matter  is  the  iron  compound  of  nitroso- 
naphthol-mono-sulphonic  acid.  It  gives  an  olive-green 
colour  on  wool,  remarkable  for  its  fastness  to  light.  The 


76    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


colour  also  bears  the  action  of  milling  with  soap  fairly 
well,  but  it  is  much  impoverished  by  the  action  of  car- 
bonate of  soda.  Naphthol  Green  is  not  applicable  in  cot- 
ton-dyeing. 

Application  to  Wool. — Dye  at  100°  C,  with  the  addi- 
tion of  2-3  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1'04), 
20  %  of  sodium  sulphate,  and  10  %  of  ferrous  sulphate. 
It  is  very  useful  for  producing  compound  shades  in  con- 
junction with  other  colouring  matters  which  are  applied 
in  an  acid  bath. 

(c.)  Eosolic  Acid  Colours. 

(C6H4-OH 
Aurin.  C^C6H4OH 

i  i 

This  colouring  matter  in  its  commercial  form  is  also  called 
Yellow  Corallin.  Red  Corallin  or  Peony  Eed  is  pro- 
duced from  Yellow  Corallin  by  the  action  of  ammonia  on 
it  at  high  temperatures.  Owing  to  the  extreme  fugitive- 
ness  to  light,  soap,  and  acids  of  the  colours  they  yield, 
these  colouring  matters  are  seldom  employed  in  dyeing. 
Silk  and  wool  may  be  dyed  in  a  weak  soap  bath,  heating 
it  gradually  to  the  boiling  point;  brighten  the  silk  with 
tartaric  acid.  They  are  still  used  by  the  calico  and 
woollen  printer. 

(d.)  Phthaleins. 

Fluorescein.    C  \  CBH3-OH  \  u 
C6H4-CO-0 


i  


Fluorescein  dyes  wool  and  silk  yellow  in  a  slightly  acidu- 
lated bath;  but  it  is  scarcely  used  in  dyeing,  because  it 
does  not  give  fast  colours,  and  these  are  surpassed  in 
beauty  of  tint  by  those  yielded  by  other  yellow  colouring 
matters.  Its  sodium  compound,  known  under  the  name 
of  Uranin,  is  applied  in  the  same  manner. 

(C7H3-0(C7H7)  \  n 
Chrysolin.     C  \  C6H8-OXa      j  u 
|  (C6H4  CO-0 
i  i 


This  colouring  matter  is  the  sodium  salt  of  benzyl- 
fluorescein.  It  dyes  wool  and  silk  in  a  neutral  bath, 
although  a  better  result  is  obtained  by  previously  mor~ 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  77 


danting  with  alum.  The  yellow  colour  produced  is  similar 
to  that  given  by  Turmeric,  but  it  is  said  to  be  faster  to 
light.  In  cotton-dyeing  it  may  be  used  for  topping  Quer- 
citron Bark  yellow. 

Eosins. — There  are  quite  a  number  of  red  colouring 
matters  belonging  to  the  class  of  Eosins.  They  differ  from 
each  other  both  in  their  composition  and  the  shade  they 
produce. 

(C6HBiyOK|n 

Eosin  J  (soluble  in  water).    C  ^CpHBivOK  j  u 

|  (CBH4-CO-0 

i  i 

This  is  the  potassium  salt  of  tetra-brom-fluorescein.  It 
dyes  a  yellowish-pink  shade. 

Eosin  B  (soluble  in  water)  is  an  alkali  salt  of  tetra- 
iodo-fluorescein,  and  dyes  a  bluish-pink  shade.  It  is  also 
known  by  the  names  Erythrosin,  Pyrosin  B  (P.  Monnet), 
and  Soluble  Primrose  (Durand  and  Huguenin). 

Aureosin  (Willm,  B.  &  Girard)  is  a  chlorinated 
fluorescein. 

Rubeosin  (Willm,  B.  &  Girard)  is  a  nitro-chlor- 
fluorescein. 

Eosin  BN  (basf),  also  called  Saf rosin  (Soc.  Chem.  Ind., 
Basle),  is  a  brom-nitro-fiuorescein. 

Lutecienne  (Poirrier)  is  a  mixture  of  brom-nitro- 
fluorescein,  with  di-  and  tetra-nitro-fluorescein  or  Poir- 
rier's  Orange  2. 

Nopalin  and  Imperial  Red  contain  dinitro-naphthol 
mixed  with  brom-nitro-fluorescein. 

Coccin  is  a  mixture  of  Aurantia  with  brom-nitro- 
fluorescein. 

Eosin  (soluble  in  alcohol)  is  the  potassium  salt  of 
tetra-brom-fluorescein-methyl  or  ethyl-ether.  It  bears  also 
such  names  as  Methyl-eosin,  Ethyl-eosin,  Primrose  (solu- 
ble in  alcohol),  Rose  JB,  Erythrin,  Methyl-erythrin,  etc. 

The  methyl  compounds  gives  yellower  shades  than  the 
ethyl  compound.  Both  give  better  and  brighter  shades 
than  the  ordinary  eosins,  which  they  have  largely  dis- 
placed in  silk-dyeing. 

Rose  Bengal  is  the  sodium  salt  of  tetra-iodo-dichlor- 
fluorescein. 

Phloxin?{¥.  Monnet  &  Co.)  is  the  potassium  salt  of 
tetra-brom-dichlor-fluorescein. 


78    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Gyanosin  (P.  Monnet  &  Co.)  is  the  potassium  salt  of 
the  methyl-ether  of  Phloxin. 

The  eosins  may  be  used  in  cotton-,  wool-,  or  silk-dyeing, 
and  yield  bright  shades,  which  vary  from  yellowish- 
scarlet  to  bluish-crimson.  The  yellowest  shade  is  given 
by  Eosin  J  or  G,  then  follow  Methyl  and  Ethyl-eosin, 
Eosin  B,  Phloxin,  and  Safrosin.  The  bluest  shade  is 
given  by  Rose  Bengal.  Cyanosin,  Phloxin,  and  others 
are  sold,  however,  in  different  shades,  and  are  marked 
accordingly  with  J,  R,  or  B.  Safrosin  is  not  quite  so 
bright  on  silk  as  some  of  the  other  blue  shades,  but  on 
wool  it  gives  a  good  full  and  bright  colour. 

The  eosins  soluble  in  alcohol  give  brighter  shades  than 
those  soluble  in  water,  but,  apart  from  the  cost  of  the 
alcohol  required,  they  cannot  always  be  used,  because 
the  strong  yellowish  fluorescence  which  they  give  is  some- 
times not  desirable. 

Application  of  Eosins  to  Cotton. — Cotton  has  natur- 
ally no  attraction  for  the  eosins,  but  since  they  form 
lakes  with  metallic  oxides  (especially  protoxides),  it  is 
possible  to  dye  this  fibre  if  it  is  previously  mordanted 
with  some  metallic  salt.  The  mordants  employed  are 
those  of  zinc  and  lead.    Aluminium  salts  are  also  used. 

Impregnate  the  cotton  with  a  cold  or  tepid  solution  of 
sulphated  oil,  100  g.  =  3'2  ozs.  per  litre  =  1  quart ;  wring 
out,  dry  and  steam;  then  work  in  aluminium  acetate,  at 
8°  Tw.  (Sp.  Gr.  104)  for  \  hour,  steep  1-2  hours  longer, 
and  wring  out.  Dye  in  a  fresh  bath  of  Eosin  solution 
acidified  with  5-10  %  of  alum.  Enter  the  cotton  at  45°  C, 
and  allow  the  bath  to  cool  gradually  during  the  dyeing 
process.  A  strong  hot  solution  of  soap  may  be  substituted 
for  the  sulphated  oil,  and  a  solution  of  nitrate  acetate  or 
basic  acetate  of  lead  at  5°  Tw.  (Sp.  Gr.  1  025)  may  re- 
place the  aluminium  acetate.  The  colours  thus  obtained 
have  a  yellow  tone. 

Very  good  bluish  shades  are  produced  by  impregnat- 
ing the  cotton  with  the  lead  solution,  then  drying  and 
dyeing  in  Eosin  solution. 

The  use  of  a  lead  salt  has  the  disadvantage  that  the 
colour  is  blackened  if  exposed  to  an  atmosphere  con- 
taining sulphuretted  hydrogen.  The  dye  th^is  obtained 
is  naturally  of  a  poisonous  character. 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  79 


Application  to  Wool.— Bye  with  0  5-2  %  of  Eosin,  with 
the  addition  of  5-10  %  of  alum.  Enter  the  wool  at  40°  0., 
and  raise  the  temperature  gradually  to  100°  C.  in  the 
course  of  1  hour.  If  the  bath  is  acidified  with  acetic  or  sul- 
phuric acid  instead  of  alum,  the  shades  produced  are 
not  so  bright,  but  the  wool  is  less  harsh.  With  Erythrosin 
the  temperature  of  the  dye-bath  must  be  kept  below  the 
boiling  point. 

The  water  used  should  be  as  free  from  lime  as  possible, 
otherwise  it  causes  precipitation  and  loss  of  colouring 
matter.  If  lime  is  present,  neutralise  it  with  acetic 
acid  before  dyeing. 

Application  to  Silk. — Dye  in  a  bath  slightly  acidified 
with  acetic  or  sulphuric  acid,  with  or  without  the  addition 
of  "  boiled-off  "  liquor.  Wash  and  brighten  with  acetic 
or  tartaric  acid.  Add  the  colour  solution  gradually,  and 
heat  slowly  to  60°  C. 


This  fine  purple  colouring  matter,  sometimes  called 
Anthracene  Violet,  is  derived  from  phthalic  anhydride 
and  pyrogallol.  It  is  sold  in  the  form  of  a  reddish- 
brown  powder  or  a  10  %  paste,  not  very  soluble  in  cold 
water,  but  readily  so  in  hot.  It  gives  fine  purple  shades 
on  cotton,  wool,  and  silk,  which  are  tolerably  fast  both 
to  light  and  soap. 

Application  to  Cotton. — Prepare  the  cotton  with 
aluminium,  chromium,  or  iron  mordants  in  the  usual 
manner,  and  dye  in  a  separate  bath  with  Gallein.  The 
whole  process  is  identical  with  that  used  in  dyeing  with 
Alizarin,  Logwood,  or  other  polygenetic  colouring  matters. 

All  the  mordants  yield  purple  colours,  those  obtained 
by  the  use  of  chromium  and  iron  being  bluish,  those  of 
tin  reddish,  and  those  of  aluminium  intermediate  in  tone. 
All  the  colours  may  be  regarded  as  fast  to  light  and  soap. 

Application  to  Wool. — Mordant  the  wool  with  2  %  of 
bichromate  of  potash.  The  addition  of  sulphuric  acid, 
even  to  the  extent  of  1  %,  is  injurious,  and  dulls  the 


Galle'in, 


C 


L. 


80    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


colour.  Dye  in  a  separate  bath  with  10-20%  of  Gallein 
paste,  containing  10  %  of  solid  matter.  Enter  the  wool 
cold,  and  raise  the  temperature  gradually  to  the  boiling 
point.  The  shade  thus  produced  is  bluish-purple  or 
violet. 

With  aluminium  mordant  a  much  redder  and  brighter 
purple  is  given.  Mordant  with  6-8  %  of  aluminium  sul- 
phate and  5-7  %  of  cream  of  tartar.  With  the  addition 
of  1-2  %  of  acetate  of  lime  (solid),  the  shade  is  somewhat 
more  intense  and  slightly  brighter.  The  addition  of  chalk 
to  the  dye-bath  is  not  to  be  recomended ;  even  with  2  % 
the  colour  is  much  deteriorated.  With  iron  mordants 
Gallein  gives  a  deep  violet  colour.  Use  8  %  ferrous  sul- 
phate and  5  %  tartar.  The  single-bath  method  is  also 
applicable. 

All  the  above  Gallein  colours  are  specially  adapted  for 
goods  which  have  to  be  milled.  The  chromium  mordant 
is  the  most  generally  useful  of  those  mentioned. 

Silk  is  dyed  in  the  same  way  as  with  Alizarin. 

f  COC6H2    -  O 
Coerulein  C6H4  ">0 

|COC6H(OH)-0 

This  green  colouring  matter,  also  called  Anthracene  Green, 
is  derived  from  Gallein  by  the  action  of  sulphuric  acid 
at  a  high  temperature.  It  is  sold  in  two  forms,  either  as 
a  thick  black  paste  (Coerulein  paste)  containing  10-20  % 
of  Coerulein,  or  as  a  black  powder.  The  former  is  more 
or  less  insoluble  in  water,  and  requires  in  some  cases  the 
addition  of  bisulphite  of  soda  to  render  it  soluble.  The 
latter,  known  as  Coerulein  S,  is  soluble  in  water,  and  is 
indeed  a  compound  of  Coerulein-  with  bisulphite  of  soda 
[C20H8O6*2NaHSO3] ;  this  form  is  the  one  most  easily 
applied.  Coerulein  is  mostly  employed  in  calico-printing  for 
producing  very  fast  olive-green  shades.  The  colours  it  yields 
both  on  cotton  and  on  wool  are  remarkable  for  their  fast- 
ness to  light,  acids,  alkalis,  etc.,  and  whenever  its  price 
permits,  it  will  find  an  extensive  use  in  the  dyeing  of 
these  materials.  Whatever  the  mordant  used,  only  differ- 
ent shades  of  olive-green  are  obtained.  The  use  of  copper 
dye-vessels  should  be  avoided. 

^  Application  to  Cotton.— It  insoluble  Coerulein  is  heated 
with  a  mixture  of  caustic  alkali  (NH3)  and  zinc  powder, 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  81 


a  brownish-red  solution  of  the  reduction  product  Coerulein 
is  obtained,  which,  on  exposure  to  air,  immediately  be- 
comes green  again,  with  precipitation  of  the  original 
Coerulein.  This  brownish-red  liquid,  or  "  Coerulein-vat,;; 
as  it  might  be  termed,  may  be  used  for  dyeing  after 
the  manner  of  the  Indigo-vat. 

If  the  soluble  Coerulein  S  is  employed,  the  cotton 
must  be  previously  prepared  with  aluminium,  chromium, 
iron,  or  tin  mordant,  according  to  the  usual  methods,  and 
then  dyed  in  a  simple  solution  of  the  colouring  matter. 
Care  should  be  taken  to  begin  dyeing  at  a  low  tempera- 
ture, and  to  raise  it  very  gradually  to  100°  C.  During 
the  dyeing  process  sulphurous  acid  is  given  off,  and  the 
liquid  becomes  green  and  alkaline.  The  water  employed 
should  be  free  from  salts  of  lime  and  other  alkaline  earths, 
since  these  produce  insoluble  lakes  with  Coerulein.  The 
insoluble  form  of  Coerulein  may  be  applied  in  the  same 
way,  if  bisulphite  of  soda  is  added  to  the  bath  to  render  it 
soluble,  but  the  results  are  not  quite  so  satisfactory. 

Application  to  Wool. — Mordant  with  2-3  %  bichromate  of 
potash  and  0-0*7  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1'84). 
Without  sulphuric  acid  the  colour  is  slightly  paler.  Dye  in 
a  separate  bath  containing  only  Coerulein  S.  Enter  the 
wool  cold,  and  raise  the  temperature  very  gradually  (say 
in  the  course  of  J  hour)  to  60°  C.  Dye  at  this  temperature 
for  about  1  hour,  then  heat  gradually  in  the  course  of 
\  hour  to  100°  C,  and  boil  for  \  hour.  The  addition  to 
the  dye-bath,  during  the  last  \  hour,  of  1-2  %  of  chalk, 
makes  the  shade  bluer,  but  generally  speaking  the  addi- 
tion of  chalk  or  calcium  acetate  to  the  bath  is  to  be 
avoided.  With*  2  %  of  Coerulein  S  a  pale  sage-green  is 
obtained,  with  5  %  a  medium  olive-green,  and  with  10  % 
a  very  dark  green,  almost  black.  These  colours  may  be 
used  instead  of  Indigo-greens,  being  equally  fast  to  light, 
milling,  etc. 

With  aluminium  mordant  shades  can  be  obtained  which 
are  somewhat  bluer  or  greyer  than  with  bichromate  of 
potash,  but  they  are  very  apt  to  be  uneven. 

With  iron  mordant  dirty  olive  and  olive-black  shades 
are  obtained.  Use  4  %  of  ferrous  sulphate  and  8  %  of 
cream  of  tartar,  and  dye  with  0*5-10  %  of  Coerulein  S. 

If  wool  is  mordanted  with  an  amount  of  pure  stannic 
F 


82    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


chloride  equivalent  to  5  %  SnCl2'2H20  (tin-crystals),  it 
needs  the  addition  of  40  %  of  cream  of  tartar  to  yield 
a  normal  bluish-green  colour,  when  dyed  afterwards  with 
5  %  of  Cosrulein  S ;  but  it  is  remarkable  that  even 
without  the  addition  of  any  tartar  a  full  greyish-black 
colour  is  obtained.  (With  the  majority  of  polygenetic 
colouring  matters,  stannic  chloride  is  an  unsatisfactory 
mordant.)  With  5  %  of  Ccerulein  S,  the  colour  is  perhaps 
too  much  like  a  bad  black  to  be  of  general  use,  but  with 
0'5-2  %  very  pleasing  greys  are  obtained. 

Application  to  Silk. — Ccerulein  has  scarcely  been  intro- 
duced into  silk-dyeing,  though  it  is  capable  of  giving 
good  fast  shades.  Mordant  in  the  usual  manner  with 
alum,  dye  in  a  separate  bath  with  Coerule'in  S,  and 
brighten  with  a  solution  of  soap. 

(e.)  1 nolo phenols. 
a-Na/phthol  Blue  (L.  Casella  &  Co.). 

u6n4|N  =  C10H6(OH) 

Dimethyl-ainido-phenyl-oxy-naphthylamine. 

— This  colouring  matter,  also  called  Indophenol  Blue  N,  is 
produced  by  oxidising  a  mixture  of  dimethy]-p-phenylene- 
diamine  and  a-naphthol,  or  by  the  action  of  nitroso- 
dimethyl-aniline  on  a-naphthol.  It  gives  colours  very 
similar  to  vat-indigo  blues,  and  which  are  said  to  be 
moderately  fast  to  light.  They  are,  however,  extremely 
sensitive  to  the  action  of  acids;  even  weak  acids  destroy 
the  blue  colour  and  change  it  to  brown.  Indophenol 
Blue  N  is  better  adapted  for  woollen-  and  calico-printing 
than  for  dyeing. 

Under  the  influence  of  reducing  agents — e.g.  glucose 
and  caustic  soda,  stannous  chloride  and  carbonate  of 
soda,  etc. — Indophenol  Blue  is  changed  into  Indophenol- 
White,  which  is  soluble  in  pure  or  acidulated  water. 

For  the  preparation  of  indophenol-white,  mix  together 
10  kg.  =  22  0  lb.  of  Indophenol  Blue  (paste)  and  60  litres 
=  132  gals,  of  water;  add  30  litres  =  6*6  gals,  of  a  10  % 
solution  of  tin  crystals  (SnCl2"2H20),  and  heat  to  25°  C. 
until  reduction  takes  place. 

Application  to  Cotton.— Dye  for  10  minutes  at  40°  C. 
in  a  solution  containing  5-10  g.    ==  77  1-154'3  grains  of 


QUINOLINE  AND  PHENOL  COLOURING  MATTERS.  83 


indophenol-white  per  litre,  then  wring  out  and  wash, 
and  develop  the  colour  by  working  the  cotton  for 
about  2  minutes  at  50°  C.  in  a  dilute  solution  of  bichromate 
of  potash.  Better  colours  are  obtained  if  the  cotton  is 
previously  prepared  with  sulphated  oil. 

Application  to  Wool. — Dye  for  15  minutes  at  80°  C. 
in  a  solution  of  indophenol-white,  rendered  either  alkaline 
by  the  addition  of  sodium  carbonate,  or  acid  by  means 
of  acetic  acid.  Wring  out,  wash,  and  develop  the  colour 
by  exposure  to  air,  or  by  working  the  material  for  a  few 
minutes  in  cold  dilute  solution  of  bichromate  of  potash, 
or  an  ammoniacal  solution  of  sulphate  of  copper.  For 
dark  shades  the  solution  of  indophenol-white  should  be 
concentrated;  the  dye-bath  is  not  exhausted,  and  should 
always  be  preserved. 

Gallocyanin  (Durand  and  Huguenin). — This  colouring 
matter,  also  called  New  Fast  Violet,  is  obtained  by  the 
action  of  nitroso-dimethyl-aniline  on  tannic  acid.  In  dye- 
ing, it  yields  a  bluish-violet  colour  possessing  only 
moderate  brilliancy,  but  tolerably  fast  to  the  action  of 
acids,  alkalis,  and  light.  Applied  in  conjunction  with 
other  colouring  matters,  it  is  useful  for  obtaining  com- 
pound shades. 

Application  to  Cotton. — Mordant  the  cotton  by  means 
of  an  alkaline  solution  of  chromium  oxide,  and  wash  well. 
Dye  in  a  separate  bath  with  Gallocyanin,  at  a  tempera- 
ture of  80°  C,  for  1-1  \  hour.  If,  after  dyeing,  the  cotton 
is  washed,  dried,  and  steamed,  the  colour  becomes  some- 
what darker  and  faster. 

Application  to  Wool. — The  wool  may  be  dyed  without 
any  previous  preparation,  or  it  may  be  first  mordanted  in 
the  usual  manner  with  bichromate  of  potash.  Dye  in  a 
neutral  bath.  Introduce  the  wool  into  a  cold  solution, 
raise  the  temperature  gradually  to  70°  C.  in  the  course  of 
1  hour,  and  continue  dyeing  for  ^-1  hour  longer. 

Application  to  Silk. — Dye  at  70°-80°  C.  in  a  bath  con- 
taining colour  solution  and  "  boiled-off "  liquor.  The 
silk  may  be  previously  mordanted  with  chrome  alum, 
though  this  is  not  absolutely  necessary. 


81 


CHAPTER  VI. 

AZO     COLOURING  MATTERS. 

(a.)  Amido-azo-colours. 
Aniline    Yellow    [C6H5-N     =    NC6H4NH2HC1].—  This 

Diamido-azo-benzene-hydrochloride. 

colouring  matter  is  no  longer  used  in  dyeing,  because 
the  colour  which  it  yields  is  volatile  and  not  fast.  Cotton 
has  no  attraction  for  it.  Wool  and  silk  may  be  dyed 
in  a  bath  slightly  acidified  with  acetic  acid. 

Chrysoidine    [C0HS"N    =    N  C6H3(NH2)2  HC1].—  This 

Diamido-azo-benzene-hydrochlor  d  . 

colouring  matter,  much  used  in  cotton-dyeing  for  produc- 
ing various  shades  of  orange,  is  prepared  by  the  action  of 
diazo-benzene-chloride  on  m-phenylene-diamine.  It  is  well 
adapted  for  shading,  and  may  be  used  as  the  yellow  part 
in  a  number  of  compound  shades — e.g.  olive,  brown,  scar- 
let, etc.  Chrysoidine  FF  (L.  Casella  &  Co.)  is  the  corre- 
sponding toluene  compound. 

Application  to  Cotton. — Mordant  the  cotton  with  tan- 
nic acid  and  tartar  emetic,  and  wash ;  dye  at  60°  C.  in 
a  solution  of  the  colouring  matter,  without  any  further 
addition.  Avoid  high  temperatures,  since  the  colour  is 
thereby  rendered  duller. 

Sometimes  the  fixing  of  the  tannic  acid  with  tartar 
emetic  may  be  omitted,  and  for  very  light  shades  it  is 
not  even  necessary  to  prepare  the  cotton  with  tannic 
acid,  since  this  fibre  seems  to  possess  naturally  a  certain 
attraction  for  Chrysoidine.  Good  shades  are  obtained  by 
applying  Chrysoidine  to  cotton  previously  dyed  with 
Catechu,  Sumach,  etc. 

Application  to  Wool. — Dye  at  60°-70°  C.  in  a  neutral 
bath,  or  with  the  addition  of  2-4  %  of  soap,  or  one  acidified 
with  alum.  These  additions  tend  to  brighten  the  colour. 
The  addition  of  sulphuric  acid  to  the  dye-bath  im- 
poverishes the  colour,  but  if,  after  dyeing  according  to 
the  above  method,  the  wool  be  worked  for  10-15  minutes 
in  cold  water  slightly  acidified  with  sulphuric  acid,  the 


AZO  COLOURING  MATTERS, 


85 


colour  acquires  a  deeper  and  redder  hue.  Dyeing  at  100° 
C.  dulls  the  colour  considerably. 

Application  to  Silk. — Dye  at  a  temperature  of  60°  C, 
with  or  without  the  addition  of  a  little  soap  to  the  dye- 
bath.  Brighten  in  a  bath  very  slightly  acidified  with 
sulphuric  acid. 

Phenylene  Brown. — 

[C6H4-(NH2)-N  =  N-C6H3(NH2)2-2HC1]. 

Trianiido-azo-benzene-hydrochloride. 

This  colouring  matter  is  prepared  by  the  action  of  nitrous 
acid  on  m-phenylene-diamine,  and  dissolving  the  base 
thus  produced  in  hydrochloric  acid.  It  also  bears  the 
commercial  names  :  Bismarck  Brown,  Vesuvine,  Canelle, 
Manchester  Brown,  Cinnamon  Brown,  etc.  Bismarck 
Brown  GG  and  EE(L.  Casella  &  Co.)  are  the  pure  pro- 
ducts of  toluylene-diamine  and  phenylene-diamine  respec- 
tively. 

Application  to  Cotton. — Prepare  the  cotton  with  tan- 
nic acid  and  tartar  emetic ;  wash  and  dye  in  a  neutral 
bath  at  50°-60°  C.  Add  the  colour  solution  gradually. 
A  slight  addition  of  alum  to  the  dye-bath  may  sometimes 
be  made  to  modify  the  shade.  The  shades  given  by  Bis- 
marck Brown  are  similar  to  those  obtained  from  Catechu, 
but,  as  a  rule,  brighter.  Light  shades  can  be  dyed  with- 
out previous  preparation  of  the  cotton.  Catechu  browns 
are  frequently  dyed  with  it  in  order  to  brighten  or  modify 
the  colour. 

A  great  variety  of  compound  colours  are  obtainable 
by  using  it  along  with  other  basic  colouring  matters — e.g. 
Magenta,  Malachite  Green,  Methyl  Violet,  Methylene 
Blue,  etc. 

Application  to  Wool. — Dye  in  a  neutral  bath.  For  a 
full  shade,  use  5-8  %  of  colouring  matter.  The  addition 
of  8-10  %  of  alum  to  the  bath  makes  the  shade  redder. 
Enter  the  wool  at  45°  C,  and  heat  gradually  to  100°  C. 

Application  to  Silk. — Dye  in  a  weak  soap  bath  at 
60°  C,  and  brighten  in  a  fresh  bath  slightly  acidified  with 
acetic  or  tartaric  acid. 

(b.)  Amido-azo-sulphonic  Acids. 
Fast  Yellow. — 

[(SO,Na)C,H/N  =  N'CtH4(NH2)]. 

Amido-azo-benzene-sodium-]>sulplionate. 


86    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


This  colouring  matter  is  also  called  Acid  Yellow ;  it  cannot 
be  used  for  dyeing  cotton.  It  is  well  adapted  for  using 
along  with  other  acid  colouring  matters  to  obtain  com- 
pound shades  on  wool  or  silk.  Employed  alone,  it  can- 
not compete  with  some  other  yellows  in  brilliancy.  The 
above  compound  is  sometimes  distinguished  as  Fast  Yellow 
G,  while  Fast  Yellow  R  is  given  to  the  corresponding 
toluene  compound. 

Application  to  Wool. — Dye  in  an  acid  bath.  For 
0'5-3  %  of  colouring  matter  add  2-6  %  of  sulphuric  acid, 
168°  Tw.  (Sp.  Gr.  1'84).  Enter  the  wool  at  40°  C,  and 
heat  gradually  to  100°  C.  in  the  course  of  f-1  hour,  and 
boil  for  J  hour.  If  5-10  %  of  alum  be  used  instead  of 
sulphuric  acid,  the  shade  given  is  weaker  and  less  orange. 

Application  to  Silk. — Dye  at  a  temperature  of 
60°-80°  C,  in  a  bath  containing  "  boiled-off  ?;  liquor  and 
acidified  with  sulphuric  acid. 

Dim  ethyl  aniline  Orange. — 

[(S03-NH4)CeH4-N  =  N-C6H4(N(CH3)2)]. 

p-Dimethyl-ainiclo-azo-benzene-amiiioniuni-p-sulphonate. 

Other  commercial  names  of  this  colouring  matter  are  : 
Helianthin,  Gold  Orange,  Orange  III.,  and  Tropseolin  D, 
etc. 

Application  to  Cotton. — Work  the  cotton  in  cold  stan- 
nate  of  soda  solution,  5°  Tw.  (Sp.  Gr.  1  025),  till 
thoroughly  saturated,  and  wring  out ;  work  for  l~h  hour 
in  a  cold  solution  of  alum  (15-20  %),  and  wring  out; 
dye  in  a  concentrated  solution  of  the  colouring  matter, 
with  the  addition  of  an  equal  percentage  of  alum.  Enter 
cold,  and  heat  gradually  to  45°  C,  but  not  higher.  Dry 
without  previous  washing.  The  colour  is  not  fast  to 
washing. 

Application  to  Wool. — Dye  exactly  as  with  Fast  Yellow. 
Somewhat  brighter  shades  are  obtained  by  using  stannic 
chloride  instead  of  sulphuric  acid.  With  2  %  of  colouring 
matter  a  full  reddish-orange  is  obtained. 

Application  to  Silk. — Dye  exactly  as  with  Fast  Yellow. 

Biphenyl  amine  Orange. — 

[(SO^K)G6H4-N  =  N-C6H4(N-H-C6H5)] 

29-Phenyl-aii)ido-azo-benzeiie-potassiuin-p-sulphonate. 

This   colouring   matter    is    also   called    Tropseolin  OO, 


AZO   COLOURING  MATTERS. 


87 


Orange  IV.,  Orange  N,  Yellow  N,  etc.  It  is  very  sensi- 
tive to  the  action  of  an  excess  of  free  acid,  which  causes 
it  to  dye  a  more  orange  colour.  Large  excess  of  mineral 
acid  causes  its  solutions  to  become  violet  through  libera- 
tion of  the  free  colour  acid.  Closely  allied  to  this  colour- 
ing matter  are  the  three  following  : — 
Met  an  if  Yellow  (basf). — 

[(S0fNa)CGH/N  =  N  C6H4(N  H  C6H5)] 

p-Phenyl-ainido-azo-beiizene-sodium-/)i-sulphonate. 

This  colouring  matter  is  also  called  Tropseolin  G 
(L.  Cassella  &  Co.). 

Brilliant  Yellow  (basf). — 

[(S03Na)CGH3(CH3)-N  =  N  CGH4(N  H  C6H5)] 

p-Phenyl-amido-azo-toluene  sodium-^-sulphonate. 
A zo flavin  2  (basf). — 

[(S03Na)C6H4-N  =  N-06H4(N'H-CeH4(N02))] 

2)-Nitro-plienyl-amido-azo-benzene-sodiuin-2)-sulphonate. 

All  these  colouring  matters  are  specially  suitable  for  wool- 
and  silk-dyeing,  and  give  fine  yellow  or  orange  shades. 
They  are  applied  in  the  same  way  as  Fast  Yellow  and 
Dimethylanine  Orange.  The  colours  on  cotton  are  not 
fast  to  washing.  If  10  %  of  alum  is  added  to  the  dye- 
bath  instead  of  sulphuric  acid,  the  colours  on  wool  are 
rendered  brighter. 

Indian  Yellow  (L.  Casella  &  Co.)  is  isomeric  with 
Azofiavin. 

Congo  Bed  (Berlin  Aniline  Co.). — 

j  C6H4-N  =  N-Cl0H5(NH2)(SO3Naj 

(  C6H4-N  =  N-Cl0H5(NH2)(SO3Na) 
Tetrazo-diplienyl-dinaphtliylamine-sodiuni-disulphonate. 

This  colouring  matter  possesses  the  very  interesting  pro- 
perty of  being  readily  applied  to  the  vegetable  fibres 
without  the  aid  of  a  mordant.  It  may  be  used  for  dyeing 
mixed  goods  consisting  of  cotton  and  wool,  and  yields 
a  bright  scarlet  colour,  fairly  fast  to  boiling  soap  solu- 
tions, but  not  to  light.  It  is  also  extremely  sensitive  to 
the  action  of  acids ;  these  change  the  colour  to  blue. 

Application  to  Cotton. — Dye  at  100°  C.  in  a  neutral 
bath,  or  one  rendered  slightly  alkaline  by  the  addition 
of  soap ;  wash  and  dry.    A  much  richer  colour  is  got 


83    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


if  the  cotton  is  previously  mordanted  with  stannic  oxide, 
or,  better  still,  with  sulphated  oil  and  aluminium  sul- 
phate. 

Application  to  Wool  and  Silk.— Bye  in  a  neutral  bath 
or  with  the  addition  of  a  little  soap. 
Benzopurpurin  (Bayer  &  Co.). — 

(  C7H6-X  =  N-Cl0H5(NH2)(SO3Na) 

\  C7H,-N  =  N-Cl0H5(NH2)(SO3Na) 
Tetrazo-ditolyl-diphenylamine-sodium-disulplionate. 

This  colouring  matter  is  applied  to  the  various  fibres  in 
the  same  manner  as  Congo  Red,  being  closely  allied  to 
it  in  chemical  constitution.  It  yields  a  bright  scarlet 
colour,  fairly  fast  to  soap,  and  less  sensitive  to  light  and 
particularly  to  acids,  than  Congo  Red.  It  is  not  affected 
by  dilute  acetic  acid,  or  even  by  dilute  mineral  acids. 
The  best  addition  to  make  to  the  dye-bath  is  phosphate  of 
soda,  though  one  may,  if  desirable,  use  soap  or  silicate  of 
soda  instead. 

(c.)  Oxy-azo  Colouring  Matters. 

These  include  yellow,  orange,  red,  crimson,  and 
brown  colours.  Nearly  all  belong  to  the  class  of  so-called 
acid-colours,  and  are  specially  suitable  for  wool-  and  silk- 
dyeing.  When  applied  to  cotton,  most  of  the  colours  are 
not  fast  to  washing  with  water. 

Many  of  the  scarlets  have  largely  displaced  Cochineal 
in  wool-dyeing.  For  plain  scarlet  dyes  (on  flannels,  etc.) 
they  are  even  preferable  to  Cochineal,  since  the  colour 
does  not  become  dull  and  bluish  on  washing  with  soap. 
They  are,  however,  not  suitable  for  yarn  which  has  to  be 
vvoven  with  other  light-coloured  yarns,  if  the  material  so 
produced  must  afterwards  be  washed  with  soap,  scoured, 
or  milled.  During  these  processes  the  colour  "  bleeds," 
or  comes  off  slightly  and  dyes  very  permanently  the  con- 
tiguous light-coloured  fibres,  thus  spoiling  the  general 
appearance  of  the  fabric.  This  defect  is  common,  indeed, 
to  all  those  coal-tar  colouring  matters  which  dye  without 
mordant,  For  dark-coloured  fabrics  the  defect  is  not 
noticeable. 

The  dyeing  properties  of  many  of  these  colouring 
matters  are  very  similar. 


AZO  COLOURING  MATTERS. 


89 


The  dyes  they  yield  are  very  fairly  fast  to  light, 
though  they  differ  considerably  in  this  respect.  As  a 
rule,  the  tetrazo  compounds  are  faster  to  light  than  the 
diazo  compounds. 

It  is  difficult  to  identify  all  the  colouring  matters  of 
this  class  met  with  in  commerce,  since  each  manufacturer 
gives  a  special  name  and  mark  to  his  own  products.  The 
following  list,  however,  gives  a  selection  : — 

Tropceolin  ¥. — 

[(S03Na)CGH/N  =  N  C6H4  (OH)] 

p-Pheiiol-azo-benzene-sodinm-/)  sulphonate. 

This  colouring  matter  has  now  little  importance,  having 
been  replaced  by  other  similar  but  superior  colouring 
matters. 

Resorcinol  Yellow. — 

[(S03Na)C6H4;N  =  N-CGH3(OH2)] 

Resorcinol-azo-benzene-sodium  -^-sulphonate. 

This  colouring  matter  is  also  called  Tropseolin  O,  Tro- 
pseolin  R,  Chryseolin,  Chrysoin  (Poirrier).  It  gives  an 
orange  dye  of  only  moderate  brilliancy,  and  is  chiefly 
used  along  with  other  acid-colours  to  produce  olives, 
maroons,  etc. 

Orchil  Brown  (Bayer  &  Co.). — 

[(N.H2)C10H6-N  =  N-C6H4(S03Na)]. 

This  colouring  matter  is  a-naphthylamine-azo-benzene- 
sodium-sulphonate. 

Azarin  S  (m.  l.  &  b.). — 
(  OH 

C6H2ClJ  N  =  K-C10H7(OH) 
[  S03NH4-H 

This  colouring  matter  is  suitable  only  for  cotton.  It 
yields  a  brilliant  red,  said  to  be  fairly  fast  to  light. 

The  following  method  of  applying  it  to  calico  is  pro- 
posed by  the  manufacturers  : — 

Pad  the  cloth  with  a  solution  of  aluminium  acetate  to 
which  a  small  proportion  of  stannous  oxide  has  been 
added.  After  drying  and  ageing  for  12  hours,  work  the 
cloth  for  i  hour  in  a  cold  solution  containing  a  very 
small  proportion  of  acetate  of  lime  and  sodium  carbonate; 
then  wash  well  and  dye  in  a  solution  of  the  colouring 


90    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


matter,  with  the  addition  of  a  little  sulphated  oil.  After 
dyeing,  wash,  dry,  pad  with  a  dilute  solution  of  sulphated 
oil,  dry  and  steam ;  then  wash  in  a  cold  weak  soap  solu- 
tion and  dry.  The  alkalinity  of  the  soap  gives  the  red 
a  bluish  tone,  which  may  be  removed  by  a  final  passage 
in  very  dilute  acid. 

Azo  Blue  (Bayer  &  Co.). — 

j€VH6-N  =  N-O10H,(OHj(SD8K) 
(  C7Htf-N  =  N-Cl0H5(OH)(SO3K) 

Tetrazo-ditolyl-j3-napthol-potassium-disulphonate. 

This  was  the  first  blue  colouring  matter  of  the  azo  series, 
which  possessed  the  property  of  dyeing  vegetable  fibres 
without  the  aid  of  a  mordant.  It  yields  a  reddish-blue 
colour,  fast  to  soap  and  concentrated  mineral  acids,  and 
moderately  fast  to  light. 

It  is  applied  in  dyeing  in  the  same  manner  as  Benzo- 
purpurin  and  Chrysamin,  with  which  it  may  therefore 
be  used  in  the  same  bath  for  the  purpose  of  obtaining 
compound  shades  on  cotton  mixed  goods,  etc. 

Chrysamin  (Bayer  &  Co.). — 

(  CGH4-N  =  N-C6H3(OH)(COONa) 

1  C56H4'N  =  N-C6H3(OH)(COONa) 
Tetrazo-diphenyl  diphenol-sodium-a-carbonate. 

This  colouring  matter  dyes  the  vegetable  fibres  without 
the  aid  of  a  mordant  in  the  same  manner  as  Congo  Bed, 
Benzopurpurin,  and  Azo  Blue. 

The  colour  obtained  on  cotton  by  the  aid  of  a  boiling 
soap-bath  is  a  sulphur-yellow  remarkably  fast  to  light ; 
also  fast  to  acetic  acid,  but  not  to  mineral  acids. 

a-Naphthol  Orange. — 

[(SO,Na)C6H4'N  -  N'«C10H6OH)] 

a-Naphthol-azo-benzene-sodiinn-p-sulphonate. 

This  colouring  matter  is  also  called  Tropseolin  OOO  No.  1, 
Orange  No.  1  (Poirrier).  It  dyes  a  very  reddish-orange 
shade. 

fi-Napthol  Orange. — 

[(S03Na)C6H4'N  =  N/3C10H6OH)] 

/3-Naphthol-azo-benzene-sodiuiii-p-sulplionate. 

This  colouring  matter  also  bears  the  names  :  Tropaeolin 
000  No.  2,  Orange  No.  2  (basf)  (foirrier),  Orange  extra 


AZO   COLOURING  MATTERS. 


91 


(L.  Casella  &  Co.),  Mandarin  S  (Berlin  Aniline  Co.), 
Chrysaurein.  It  dyes  a  bright  reddish-orange  shade,  simi- 
lar to  that  yielded  by  Tropseolin  OOO  No.  1.  A  mixture 
of  Tropseolin  000  No.  2  and  Fast  Red  is  sometimes 
sold  under  the  name  of  French  Red  (rouge  Frangais). 
Tropseolin  000  No.  2  is  largely  used,  both  alone  and 
along  with  Indigo  Carmine  and  other  acid-colours,  for 
producing  browns,  olives,  etc. 
Trapceolin  0000.— 

[C6H5N  =  N-/3C10H5(OH)(SO3Na)] 

Beiizene-azo-jS-naphthol-sodium-a-sulphonate. 

Orange  G  (m.  l.  &  B.). — 

[C6H5-N  =  N-/3C10H4(OH)(SO3Na)2] 

Beiizene-azo-/3-raphthol-sodmin-/?-disulphonate. 

This  colouring  matter  dyes  a  bright  orange,  somewhat 
less  red  than  Tropseolin  000  No.  2,  which  is  extremely 
fast  to  light. 

Scarlet  GT  (Bayer  &  Co.).— 

[C6H4(CH3)-N  =  N-f3C10H5(OH)(SO3Na)] 

Toluerie-azo-/3-napljthol-sodiuiii-j3-sulplionate. 

Xylidine  Scarlet  G  (m.  l.  &  B.). — 

[C6H3(CH3)2'N  =  NC10H5(OH)(SO3Na)] 

o-Xylei]e-azo-/3-nax)htliol-sodiuni-j3-sulphonate. 

Scarlet  R  (Bayer  &  Co.)  is  the  isomeric  m-xylene  com- 
pound. 

This  colouring  matter  seems  to  be  identical  with 
Scarlet  2  R  (Berlin  Aniline  Co.).  Scarlet  G  (basf)  is  the 
closely-allied  jp-xylene-azo-/3-naphthol-sodium-a-disulphonate. 

Xylidine  Scarlet  E  (m.  l.  &  b.).— This  colouring 
matter  is  isomeric  with  the  last,  and  is  the  sodium  sal :  of 
the  corresponding  /3-disulphonic  acid  compound.  It  is 
sometimes  simply  called  Scarlet  R.  As  the  mark  (R) 
implies,  it  dyes  a  redder  shade  than  Scarlet  G.  Scarlet 
R  (basf)  is  the  isomeric  p-m-xylene-azo-/3  naphthol- 
sodium-disulphonate. 

Scarlet  G  G  (m.  l.  &  b.). — 

[C6H2(CH3)3-N  =  N'C10H4(OH)(SO3Na)2] 

Cumene-azo-/3-naphthol-sodium-/3-disulplionate. 

This  colouring  matter  seems  to  be  identical  or  isomeric 
with  Scarlet  4  R  (Berlin  Aniline  Co.). 


92    COLOURING  MAT  TEES  FOB  DYEING  TEXTILES. 

Scarlet  R  R. — This  colouring  matter  is  isomeric  with 
the  last,  and  is  the  sodium  salt  of  the  corresponding 
a-disulphonic  acid. 

Another  very  closely  allied  colouring  matter,  also 
called  Scarlet  R  R,  is  the  following  : 

[C6H2'(CH3)2(C2H5)-N  =  N-C10H4(OH)(SO3Na)2] 

Ethyl-xylene-azo-j3-naphthol-sodiutn-a-disulphonate. 

Scarlet  3  R  (m.  l.  &  b.). — 
[C6H2(C2H5)(CH3)2-N  =  N'C10H4(OH)(SO3Na)2] 

Ethyl-diinetliyl-azo-^-implithol-sodiuin-disulphonate. 

Scarlet  3  R  (basf). — 

[C6H2(CH3)3'N  =  N'C10H4(OH)(SO3Na)2] 

Pseudo-cumene-azo-/0-naphthol-sodium-disulphonate. 

Scarlet  4  R  (m.  l.  &  B.). — 

[C6H2(CH3)3'N  =  N-C10H4(OH)(SO3Na)2] 

Cumene-azo-jS-naphthol-sodium-disulphonate. 

Fast  Brown  (m.  l.  &  b.). — 

[(S03Na)CGH2(CH3)2-N  =  NaC10H6(OH)] 

a-Naphthol-azo-xylene-sodiuin  sulphonate. 

Fast  Red  (basf).— 

[(SO3Na)O10H6-N  =  N'/3C10H6(OH)] 

)3-Naphthol-azo-naplithalene-sodiuni-sulphonate. 

This  colouring  matter  is  also  called  Roccellin  (Poirrier), 
Orseillin  No.  3,  Rubidin,  Rauracienne,  etc.  It  does  not 
yield  a  brilliant  red,  but  one  which  is  remarkable  for  its 
fullness  or  body.  It  is  very  useful  in  conjunction  with 
other  acid-colours  for  producing  compound  shades. 

Fast  Brown  (basf). — This  colouring  matter  is  the 
corresponding  a-naphthol  compound. 

Fast  Red  G  (basf).— 

[(NH2)C10H-N  =  N-«C10H5(OH)(SO3Na)] 

a-Naphthylainine-azo-a-naphthol-sodiuin-sulphonate. 

Groce'in  3  BX  (Bayer  &  Co.). — 

[(SO3Na)C10Hr;N  =  NC10H5(OH)(SO^a)] 

Naphtha  lene-sodium-sulphonate-azo-^-naphthol-sodium-a-sulphonate. 

Claret  Red  B  (m.  l.  &  B.). — 

[C10H/N  =  N-C10H4(OH)(SO3^a)] 

a-Naphthalene-azo-/5-naphtliol-sodium-a-disulplioi]ate. 

This  colouring  matter  is  also  called  Bordeaux  R.  If 


AZO   COLOURING  MATTERS. 


93 


alum  is  used  in  the  dye-bath  for  wool,  the  colour  is  apt  to 
be  very  uneven. 

Fast  Red  B  (basf). — This  colouring  matter  is  isomeric 
with  the  last,  being  the  sodium  salt  of  the  corresponding 
/3-sulphonic  acid.  Other  names  which  seem  to  be  given 
to  it  are  Claret  Red  R  (m.  l.  &  b.)  and  Bordeaux  G. 

Crystal  Scarlet  6  R  (L.  Casella  &  Co.). — This  colour- 
ing matter  is  also  isomeric  with  Claret  Red  B,  being  the 
sodium  salt  of  the  corresponding  y-disulphonic  acid. 

Amaranth  (m.  l.  &  b.)  also  (L.  Casella  &  Co.). — 

[(SO3Na)C10H6-N  =  N-C10H4(OH)(SO3Na)2] 

Naplithalene-azo-j3-iiaplithol-sodium-trisulplionate. 

New  Coccin  (m.  l.  &  b.);  Fast  Red  D  (basf).— These 
colouring  matters  are  isomeric  with  the  last. 

Brilliant  Scarlet  4  R  (L.  Casella  &  Co.). — This  colour- 
ing matter  is  also  isomeric  with  Amaranth,  being  the 
sodium  salt  of  the  corresponding  y-disulphonic  acid. 

Scarlet  6  R  (m.  l.  &  B.). — 

[(SO3Na)C10H6'N  =  N-C10H3(OH)(SO3Na)3] 

JN  aplithalene-azo  /3-naphthol-sodium-tetrasulphonate. 

Anisol  Red  (basf). — 

[CGH4(OCH3)\Nf  -  N-C10H5(OH)(SO3Na)] 

Anisol-azo-jS-naplithol-sodiiim-sulplioiiate. 

Phenetol  Red  (basf). — 

[CcH4(OC2H5)-N  =  N-C10H4(OH)(SO^a)2] 

Plienetol-azo-j8-naphthol-sodium-a-disuli)honate. 

This  colouring  matter  is  also  called  Cocinin  (m.  l.  &  b.). 

Coccinin  B  (m.  l.  &  b.). — This  colouring  matter  is 
closely  allied  to  the  last,  being  the  corresponding  methyl- 
p-cresyl  C6H3(OCH3)(CH3)  compound. 

Brilliant  Crocein  M  (L.  Casella  &  Co.). — 
[C6H5-N  =N-C6H4N  =  N-C10H4(OH)(SO3Na)2] 

Benzene-azo-benzene-azo-/3-naplithol-sodium-y-disulphonate. 

Scarlet  S  (Berlin  Aniline  Co.). — This  colouring  matter 
is  isomeric  with  the  last. 
Scarlet  5  R  (m.  l.  &  B.). — 
[C6H5-N  =N'C6H4-N  =  N-C10H3(OH)(SO3Na3)] 

Benzene-azo-benzene-azo-^-iiaplitliol-sodium-trisulplioiiate. 

Biebrich  Scarlet  (Kalle  &  Co.). — 
[(S03¥a)C6H4'N  =N-C6H3(S03Na)'N  =  N'C10H5(OH)] 

|3-Naphtliol-azo-benze2ie.azo-benzene-sodium-disulphonate. 


94    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


This  colouring  matter  is  identical  with  Imperial  Scarlet 
(Bayer  &  Co.). 

Fast  Scarlet  (basf). — 

,.(S03Na)C6H4'N  -  NC6H2(S03Na)N  =  NC10H5(OH)] 

j3-Napht]iol-azo-benzei]e-azo-benzene-sodium-sulphonate. 

Croceln  Scarlet  3  B  (Bayer  &  Co.). — 
[(ST)3Na)C6H4'N  -  N-C6H;N  =  N-C10Ha(OH)(SO3lTa)] 

Beiizene-sodium-^-si\lphonate-azo-benzene-azo-^-naplithol-sodium-a-sulphoi.ate. 

Crocein  Scarlet  7  B  (Bayer  &  Co.). — 

[(S03Na)C6H3(CH3)N  =  N-C6H3(CH3)N  = 
N-C10H5(OH)(SO3Na)] 

Toluene-sodium-p-sulplionate-azo-to]uene-azo-j3-naphthol-sodiiim-a-sulplionate. 

Scarlet  S  S  (Berlin  Aniline  Co.). — This  colouring 
matter  is  isomeric  with  the  last.  A  mixture  of  Xylidine 
Scarlet  and  Acid  Magenta  is  said  to  have  been  sold  under 
the  same  name. 

Application  of  the  Oxy-azo  Colours  to  Cotton. — Work 
the  cotton  \-\  hour  in  a  cold  solution  of  stannate  of  soda, 
6°-8°  Tw.  (Sp.  Gr.  1-03-1*04),  wring  out  and  pass  into  a 
cold  solution  of  alum,  4°-6°  Tw.  (Sp.  Gr.  r02-l'03)  for 
J  hour.  Wring  out,  and,  without  washing,  dye  at 
45°-50°  C,  in  a  concentrated  solution  of  the  colouring 
matter,  with  the  addition  of  5-10  %  of  alum.  Wring  out, 
and  dry  without  washing.  The  colour  does  not  withstand 
even  washing  with  water.  The  cotton  may  also  be  pre- 
viously prepared  with  sulphated  oil,  instead  of  with 
stannic  oxide,  and  then  dyed  in  the  manner  described. 

An  interesting  method  of  obtaining  faster  colours  on 
cotton  with  these  colouring  matters  is  that  included  in  the 
patents  of  Grassier  and  others. 

The  colouring  matters  used  for  wool  and  silk  are  the 
alkali  salts  of  complex  sulphonic  acids,  and  are  produced 
in  a  cold  alkaline  solution  by  the  mutual  reaction  of  azo 
compounds  upon  phenols. 

The  colouring  matter  obtained  is  soluble  if  either  the 
azo  compound  or  the  phenol,  or  both,  are  in  the  form 
of  sulphonates,  but  if  otherwise,  it  is  insoluble. 

The  insoluble  non-sulphated  colour  can  be  precipi- 
tated at  once  upon  the  cotton  fibre,  by  first  impregnating 
the  latter  with  a  cold  alkaline  solution  of  the  phenol, 


AZO  COLOURING  MATTERS. 


95 


wringing  out,  and  then  passing  it  into  a  solution  of  the 
azo  compound.  In  practice,  it  is  desirable  to  pass  again 
into  the  phenol  solution,  wring  out,  wash  and  soap 
slightly,  in  order  to  remove  loosely  adhering  colour. 

Somewhat  brighter  and  fuller  colours  are  also  obtained 
by  preparing  the  cotton  previously  with  sulphated  oil. 
Owing  to  its  instability,  the  solution  of  the  azo  compound 
should  be  prepared  only  a  short  time  before  use. 

The  dye  produced  on  the  cotton  in  this  way  bears 
washing  with  water,  and  even  with  soap  solutions,  but 
it  is  liable  to  rub  off;  it  also  withstands  the  action  of 
light  fairly  well. 

The  following  equation  represents  the  formation  of 
Xylidine  Red  in  this  way  : — 

C6H3(CH3)2N  =  N  CI  +  Cl0H7  ONa  - 

Diazo-xylene-cliloride.  Sodium-a-naphthol. 

C6H3(CH3)2N  =  NC10H0OH  +  NaCl. 

Xylidine  red. 

Application  to  Wool. — Dye  with  1-2  %  of  colouring 
matter,  with  the  addition  of  2-4  %  of  sulphuric  acid, 
168°  Tw.  (Sp.  Gr.  184),  and  15-30  %  of  sodium  sulphate. 
Enter  the  wool  at  40°-50°  C,  raise  the  temperature 
gradually,  in  the  course  of  1  hour,  to  100°  C,  and  boil 
J  hour. 

Several  of  the  colouring  matters  give  brighter  colours 
if  the  sulphuric  acid  is  replaced  by  5-10  %  of  alum,  or 
5-10  %  of  stannic  chloride,  120°  Tw.  (Sp.  Gr.  1*6).  Care 
must  always  be  taken  to  have  the  bath  sufficiently  acid  to 
develop  the  full  colouring  power;  and  if  there  is  any 
tendency  to  uneven  dyeing,  the  temperature  should  be 
raised  very  gradually. 

Application  to  Silk. — Dye  in  a  bath  containing 
"  boiled-off  "  liquor,  slightly  acidified  with  sulphuric 
acid. 

The  above  modes  of  application  do  not,  of  course, 
apply  to  Azarin  S,  Azo  Blue,  and  Chrysamin. 


96 


CHAPTER  VII. 

ANTHRACENE  COLOURING  MATTERS. 

Alizarin  [C14H602(OH)J.  —  This  valuable  colouring 
matter,  formerly  known  as  a  substance  only  obtainable 
from  Madder  root,  is  now  made  in  large  quantities  from 
the  coal-tar  product,  anthracene. 

Alizarin  is  the  best  type  of  those  colouring  matters 
which  dye  only  with  the  aid  of  a  mordant,  and  which 
yield  various  colours  according  to  the  mordant  employed 
(polygenetic  colouring  matters).  In  itself  it  has  little  or 
no  colouring  power,  having  no  affinity  for  the  vegetable 
fibres,  and  merely  imparting  a  comparatively  fugitive 
orange-brown  colour  to  the  animal  fibres.  It  possesses, 
however,  the  valuable  property  of  forming  variously- 
coloured  insoluble  precipitates  or  lakes  when  combined 
with  many  of  the  metallic  oxides,  and  it  is  on  this  pro- 
perty that  its  use  in  dyeing  depends.  Its  compound  with 
alumina  is  red,  with  stannous  oxide  orange,  with  chromic 
oxide  claret-brown,  and  with  ferric  oxide  violet.  All 
the  colours  produced  on  the  textile  fibres  by  means  of 
these  mordants  are  extremely  fast  to  light,  boiling  with 
soap  solutions,  etc. 

Very  closely  allied  to  Alizarin  are  the  colouring 
matters  Isopurpurin  or  Anthrapurpurin,  Flavopurpurin, 
and  Purpurin,  C14H502'(OH)3.  Their  method  of  applica- 
tion is  so  similar  to  that  employed  for  Alizarin  that  only 
special  reference  will  be  made  to  each  where  points  of 
difference  arise.  They  are  sold  separately  or  mixed  to- 
gether in  various  proportions,  each  manufacturer  giving 
his  own  brand  to  the  different  qualities  and  mixtures. 
It  is  customary,  for  the  sake  of  simplicity,  to  sell  them, 
whether  separate  or  mixed,  under  the  common  name, 
"  Alizarin. ?; 

Those  which  consist  entirely,  or  most  largely,  of 
Alizarin  are  called  the  blue  shades  of  Alizarin,  while 
those  in  which  Flavopurpurin  or  Isopurpurin  predomi- 


ANTHRACENE  COLOURING  MATTERS.  97 


nate,  constitute  the  yellow  shades  of  Alizarin.  These 
designations  have  arisen  because  the  former  dye  alumina 
mordanted  cotton  a  crimson  or  bluish  shade  of  red,  while 
the  latter  give  a  scarlet  or  yellow  shade  of  red. 

Application  to  Cotton. — Alizarin  serves  principally  for 
the  production  of  the  brilliant  Turkey-red  dye,  already 
referred  to  under  the  head  of  Madder.  For  this  purpose 
it  has  entirely  supplanted  Madder  and  its  commercial 
preparation  Garancin,  because  the  colours  it  yields  are 
far  more  brilliant,  quite  as  fast,  and  less  expensive. 

Turkey-red  dyeing  probably  had  its  origin  in  India. 
At  an  early  date  it  was  introduced  into  Turkey  (hence 
its  name),  and  about  the  middle  of  the  eighteenth  century 
it  began  to  be  practised  in  France. 

Since  the  publication  of  the  process  in  the  year  1765 
by  the  French  Government,  it  has  been  carried  on  largely 
in  Switzerland,  Germany,  and  Britain.  At  the  present 
time,  the  chief  seats  of  this  important  industry  are  the 
Yale  of  Leven,  near  Glasgow,  and  Elberfeld,  in  Germany. 

Numerous  alterations  and  improvements  have  been 
gradually  introduced,  until  it  has  now  reached  a  very 
high  state  of  perfection  indeed.  All  the  details  of  the 
process  now  employed  have  been  empirically  determined 
throughout  a  long  period,  and  the  successful  production 
of  the  best  Turkey-red  depends  upon  their  careful 
execution. 

Cotton  is  dyed  Turkey-red  in  the  form  of  yarn  and 
cloth.  The  process  for  yarn-dyeing  seems  to  have  experi- 
enced little  change  since  the  time  when  Madder  was  the 
dyestuff  employed,  and  may  serve  as  a  type  of  the 
older  methods  of  Turkey-red  dyeing.  It  may  be  distin- 
guished as  the  Emulsion  process. 

The  present  method  of  Turkey-red  cloth-dyeing  differs 
considerably  in  the  earlier  stages  from  that  in  vogue  for 
yarn,  and  is  known  as  Steiner's  process  (from  the  name 
of  its  inventor).  There  is,  however,  a  third  process  of 
Turkey-red  dyeing  applicable  to  both  cloth  and  yarn, 
which  represents  the  method  most  recently  introduced. 
This  may  be  termed  the  sulphated-oil  process. 

Emulsion  Process  for  Dyeing  500  kg.  =  1102'3  lb.  of 
Turkey-red  Tarn.— The,  grey  yarn  is  first  "  laced,"  i.e.  the 
skeins  constituting  each  "  head     or  "  hank  ;;  are  loosely 

G 


98    COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


fastened  together  by  the  intertwining  of  a  short  piece  of 
cotton  cord,  in  order  to  prevent  entanglement  during  the 
several  operations.  The  ends  of  the  cord  are  also  knotted, 
once  or  several  times,  for  the  purpose  of  subsequently 
recognising  the  various  lots. 

1st  Operation:  Boiling. — Boil  the  yarn  6-8  hours  with 
a  solution  of  carbonate  of  soda,  1°  Tw.  (Sp.  Gr.  1'005). 


Fig.  6.  — Turkey-red  Yarn- wringing-  Machine. 


then  wash  well  with  water,  squeeze  and  dry  in  a  stove  at 
55°-60°  C. 

2nd  Operation :  First  green  liquor. — This  liquor  is 
an  emulsion  made  up  with  75  kg.  =  165*3  lb.  of  olive  oil, 
8  kg.  =  17'6  lb.  of  sheep-dung,  about  1,000  litres  =  220  0 
gals,  of  water,  and  a  sufficiency  of  a  concentrated  solution 
of  carbonate  of  soda  to  make  the  whole  to  2°  Tw.  (Sp. 
Gr.  l'Ol). 

Work  the  hanks  of  yarn  separately  in  this  emulsion  at 


ANTHRACENE   COLOURING  MATTERS.  99 


a  temperature  of  30°-40°  C,  till  thoroughly  saturated 
(about  J  minute),  and  wring  out  as  evenly  as  possible. 
This  process  is  usually  called  "  tramping  (Fr.,  tremper, 
to  steep). 

Fig.  6  represents  the  taking-off  end  of  a  wringing 
machine  made  by  Messrs.  Duncan  Stewart  &  Co.,  Glasgow, 
and  used  in  some  Turkey-red  works  in  this  country. 

It  consists  of  two  large  discs  revolving  on  a  common 
shaft.  On  the  periphery  of  each,  and  directly  opposite 
each  other,  are  several  large  iron  hooks  connected  with 
springs,  toothed  wheels,  and  rackwork,  in  such  a  manner 
that  those  on  one  of  the  discs  are  capable  of  twisting, 
while  at  the  same  time  both  sets  of  hooks  yield  inwards 
as  the  two  discs  revolve.  The  hanks  of  yarn  are  properly 
steeped  in  the  emulsion  by  hand,  and  at  once  placed  on  a 
pair  of  the  hooks ;  as  the  discs  make  a  quarter  of  a  revolu- 
tion, the  hooks  twist  and  squeeze  out  the  excess  of  liquor ; 
during  the  next  quarter  of  the  revolution  the  hooks  un- 
twist themselves,  and  at  the  opposite  side  of  the  machine 
the  hanks  are  thrown  or  pushed  off  by  a  pair  of  strong 
upright  arms. 

Fig.  7  represents  a  tramping  machine  of  A.  Weser, 
Elberfeld,  and  used  in  Germany,  which  performs  the 
steeping  as  well  as  the  wringing,  hand-labour  being  re- 
quired only  for  putting  on  and  taking  off  the  hanks  of 
yarn.  It  consists  essentially  of  the  liquor  trough  e,  above 
which  are  situated  the  fixed  revolving  roller  b,  and  loose 
roller  A,  on  which  the  hanks  are  suspended,  d  is  an 
L-shaped  arm,  the  horizontal  portion  of  which  passes 
within  the  loop  of  the  hank  and  depresses  it  into  the 
liquor.  c  is  an  iron  cylinder  pressing  against  b,  and 
serves  to  impregnate  the  yarn  with  the  solution. 

The  various  movements  of  the  machine  are  regular  and 
automatic.  The  hank  of  yarn  is  placed  on  the  rollers  A 
and  b  when  the  arm  d  is  in  the  horizontal  position ;  the 
arm  d  at  once  falls  and  steeps  the  yarn  in  the  liquid,  and 
the  rollers  revolve  for  a  short  period ;  the  arm  D  now 
again  takes  the  horizontal  position,  the  roller  b  ceases 
to  revolve,  and  the  roller  a  first  twists,  then  untwists 
the  hank,  and  it  is  ready  to  be  removed  by  the  attendant. 

Whichever  of  the  above  machines  is  used,  the  work 
of  "  tramping  "  the  yarn  is  practically  continuous. 


100  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


ANTHRACENE  COLOURING  MATTERS.  101 


The  prepared  hanks  are  allowed  to  remain  piled  to- 
gether over-night  (12-20  hours),  and  are  then  dried  in 
the  stove.  In  this  operation  (stoving)  the  temperature 
is  raised  gradually  to  55°-60°  C,  which  is  maintained  for 
2  hours.  Care  must  be  taken  to  allow  the  escape  of  the 
steam  which  is  given  off  during  the  first  stages  of  drying, 
otherwise  the  yarn  is  apt  to  be  tendered. 

3rd  and  4th  Operations :  Second  and  third  green 
liquors. — These  are  almost  exact  repetitions  of  the  second 
operation,  the  liquor  employed  being  made  up  separately 
and  with  the  same  proportions  of  the  several  ingredients 
as  given  above.  The  sole  difference  is  that  it  is  not  neces- 
sary to  let  the  prepared  yarn  lie  in  pile  over-night;  in- 
stead of  this,  if  it  is  not  raining,  it  is  suspended  on  tin 
rods,  and  exposed  to  the  open  air  for  about  2-4  hours 
previous  to  stoving. 

It  is  evident  that,  after  stoving,  the  dry  yarn  is  charged 
with  sodium  carbonate,  and  since  it  is  very  important  that 
all  the  liquors  should  be  maintained  regularly  at  the 
same  specific  gravity,  it  is  customary  not  to  allow  the 
liquor  expressed  during  the  wringing  of  the  hanks  to  flow 
back  into  the  "  tramping  ?;  box,  except  in  the  case  of  the 
"  first  green  liquor/'  but  to  collect  it  separately,  and 
then,  if  necessary,  to  dilute  it  with  water  before  using 
again. 

The  total  amount  of  oil  used  is  about  30  %  of  the 
weight  of  yarn,  but  only  a  portion  of  this  becomes  fixed 
on  the  fibre. 

5th,  6th,  1th,  and  8th  Operations :  First,  second,  third, 
and  fourth  white  liquors. — The  solution  here  used  is  sim- 
ply carbonate  of  soda,  at  2°  Tw.  (Sp.  Gr.  1*01),  but  after 
working  the  yarn  in  it  a  short  time,  it  necessarily  becomes 
an  oil  emulsion  from  the  oil  stripped  off  the  cotton,  apart 
from  the  fact  that  it  is  always  mixed  with  the  surplus 
and  expressed  liquor  from  the  similar  operations  with 
previous  lots  of  yarn. 

The  yarn  is  "  tramped  in  the  liquor,  wrung  out, 
exposed  in  the  open  air,  and  dried  in  the  stove,  as  in  the 
previous  operations. 

9th  Operation :  Steeping. — Steep  the  yarn  during  20-24 
hours  in  water  heated  4/o  55°  .CL.  wash-  well;*  and  dry  in 
the  stove' 'at  sboufc  -60°         If  'thu^'y^rn  'cofrtains  much 


102  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


unmodified  oil,  a  solution  of  carbonate  of  soda,  at  ^°  Tw. 
(Sp.  Gr.  1  0025),  may  be  used;  in  this  case  a  second  steep- 
ing for  2  hours  in  tepid  water  is  requisite  before  washing, 
etc. 

10th  Operation :  Sumaching. — A  decoction  of  Sumach  is 
made  by  boiling  60  kg.  =  132*2  lb.  of  best  leaf  Sumach 
for  about  \  hour,  with  sufficient  water  to  make  the  cold 
filtered  solution  stand  at  lj°  Tw.  (Sp.  Gr.  1  0075).  The 
stoved  yarn,  while  still  warm,  is  steeped  in  large  vats 
in  this  decoction,  as  hot  (40°-50°  C.)  as  it  can  be  borne  by 
the  boys  who  usually  tramp  it  with  bare  feet  beneath  the 
surface  of  the  solution.  After  steeping  about  4-6  hours, 
the  solution  is  drained  off,  and  the  excess  is  removed  by 
a  hydro-extractor. 

11th  Operat  ion :  Mordanting  or  Aluming. — A  basic 
solution  of  alum  is  made  by  dissolving  ordinary  rock-alum 
in  hot  water,  and  when  nearly  cold,  adding  gradually  a 
cold  solution  of  one-fourth  its  weight  of  carbonate  of  soda 
crystals.  The  solution  is  made  to  stand  at  8°  Tw.  (Sp. 
Gr.  1*04).  Sometimes,  though  this  is  not  essential,  a 
further  addition  is  made  of  about  150-200  cm3.  =  91-122 
cubic  inches  of  "  red  liquor,"  16°  Tw.  (Sp.  Gr.  108),  and 
5-7  g.  —  77-108  grains  troy  of  tin  crystals  (SnCl2)  per  kg  == 
2*2  lb.  of  alum.  The  sumached  yarn,  while  still  damp,  is 
tramped  in  the  alum  solution  at  a  temperature  of 
40°-50°  C,  and  left  to  steep  for  24  hours.  It  is  then 
thoroughly  wTashed  and  hydro-extracted. 

12th  Operation :  Dyeing. — Dye  with  150-180  g.  =  4'8-5'7 
oz.  of  Alizarin  (10  %),  30  g.  =  462*9  grains  of  ground 
Sumach,  and  about  300  g.  =  9'6  oz.  of  bullock's  blood,  per 
kg.  =  2'£  lb.  of  cotton  yarn.  If  the  water  contains  little 
or  no  lime,  add  also  ground  chalk  in  the  proportion  of  1  % 
of  the  weight  of  Alizarin  (10  %)  employed.  The  yarn  is 
introduced  into  the  cold  solution  of  the  dye-vessel,  the 
temperature  is  gradually  raised  to  100  C.,  in  the  course 
of  1  hour,  and  the  boiling  is  continued  for  i-1  hour. 
After  dyeing,  the  yarn  is  washed,  although  this  is  not 
absolutely  necessary. 

13th  Operation:  First  Clearing. — Boil  the  yarn  for 
4  hours,  at  3-4  pounds'  pressure,  with  about  30  g.  = 
463  9  grains  of  carbonate  of  soda  crystals,  and  30  g.  = 
?62'9  grains  of  palm-oil  soap,  dissolved  in  ^  M'fuciency  of 


ANTHRACENE   COLOURING  MATTERS.  103 


water,  per  kg.  =  '2*2  lb.  of  yarn.  Wash  afterwards.  The 
"  clearing  boiler  ;y  used,  and  shown  in  Fig.  8,  and  in  plan 
in  Fig  9,  is  similar  in  construction  to  an  ordinary  low- 
pressure  bleaching  kier ;  it  is,  however,  made  of  copper 
instead  of  iron,  a  represents  the  yarn ;  b  the  lid  provided 
with  safety-valve  and  blow-off  pipe ;  c  the  perforated  false 
bottom ;  d  the  puffer-pipe ;  E  the  bonnet  for  distributing 


the  liquor  over  the  yarn ;  F  the  draw-off  pipe.  During  the 
boiling,  the  liquor  which  collects  below  the  false  bottom  is 
forced  by  the  steam  up  to  the  top  of  the  puffer-pipe,  there 
to  be  ejected  and  spread  over  the  goods.  This  action  is  of 
an  intermittent  character,  since,  after  each  ejection  of 
the  liquor,  the  pressure  of  the  steam  must  accumulate 


104  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 

below  the  false  bottom  until  it  is  again  able  to  overcome 
the  weight  of  the  column  of  water  in  the  puffer-pipe. 

\Uh  Operation:  Second  Clearing. — Boil  the  yarn  for 
1-2  hours  at  3-4  pounds7  pressure  with  a  solution  contain- 
ing 25  g.  =  385*1  grains  of  palm-oil  soap  and  \\  g.  = 
231  grains  of  tin-crystals  per  kg.  =  2  2  lb.  of  yarn.  Wash 
well  and  dry  in  an  open-air  shed.  Previous  to  drying, 
the  large  excess  of  wTater  is  removed  by  means  of  the 
hydraulic  press  represented  in  Fig.  10.  It  consists  of  a 
strong  iron  framework  D  D,  writh  a  strong,  fixed,  but 
adjustable  head  A  above,  and  a  similar  one  B  below,  at- 
tached to  the  hydraulic  piston  c,  and  thus  capable  of  being 
moved  up  or  down.    By  means  of  this  machine  a  very 


large  quantity  of  wet  yarn  may  be  rapidly  and  efficiently 
squeezed. 

The  above  fairly  represents  the  "  Emulsion  process  " 
of  Turkey-red  yarn-dyeing  as  practised  at  the  present 
time.  It  consists,  therefore,  of  a  somewhat  numerous 
series  of  operations,  occupying  usually  about  three  weeks7 
time,  and  although,  hitherto,  no  absolutely  satisfactory 
scientific  explanation  has  been  given  of  the  exact  nature 
of  the  chemical  changes  effected  by  every  detail  of  the 
whole  process,  still  their  general  character  is  tolerably  well 
understood.    The  object  of  the  frequent  steeping  in  oil- 


Fig.  9  — Plan  of  Clearing-  Boiler. 


ANTHRACENE  COLOURING  MATTERS.  105 

emulsion,  drying  in  the  open  air,  and  stoving,  is  to  im- 
pregnate the  fibre  evenly  and  thoroughly  with  oil,  and 
to  modify  it  in  such  a  manner  that  it  is  not  affected  or 
removed  by  weak  alkaline  solutions,  and  that  it  will 
attract  alumina  from  its  solutions. 

Many   kinds   of   oil   have  been   employed,   but  long 


Fig.  10.— Hydraulic  Press. 

experience  has  proved  that  olive  oil  gives  the  best  and 
most  certain  results.  The  particular  quality  of  oil  most 
suitable  for  the  purpose  is  that  obtained  by  a  second 
pressing  of  the  olives  after  they  have  somewhat  fer- 
mented and  been  steeped  in  boiling  water.  (Fr.,  huile 
tournate).    It  contains  nitrogenous  and  extractive  mat- 


106  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


ters,  which  cause  it  gradually  to  become  rancid,  particu- 
larly when  exposed  to  the  air,  i.e.  it  decomposes,  and 
a  portion  of  the  glycerine  and  fatty  acids  (margaric  and 
oleic  acids)  is  liberated.  One  of  the  chief  characteristics 
of  a  good  olive  oil  suitable  for  Turkey-red  is  that,  when 
1  measure  of  it  is  shaken  up  with  about  16  measures 
of  sodium  or  potassium  carbonate  solution,  at  3°  Tw. 
(Sp.  Gr.  1015),  it  forms  a  white  milky  liquid  or  emul- 
sion, from  which  the  oil  does  not  readily  separate  even 
after  standing  for  12-18  hours.  The  oil  which  forms  the 
most  perfect  and  permanent  emulsion  with  the  least  quan- 
tity of  potash  or  soda  is  the  best.  This  property  of 
emulsifying,  however,  can  be  readily  imparted  to  any 
oil  by  mixing  it  with  5-15  %  of  oleic  acid. 

The  exact  nature  of  the  chemical  changes  which  the 
oil  undergoes  during  exposure  to  the  air  and  stoving  is 
unknown.  It  is  probable,  however,  that,  under  the  influ- 
ence of  the  alkaline  carbonate  and  heat,  the  oil  is  decom- 
posed and  oxidised  in  such  a  manner  that  there  remains  on 
the  fibre  essentially  an  insoluble  oxyoleic  acid.  Whatever 
may  be  the  exact  chemical  composition  of  the  modified 
oil,  it  has  the  property  of  fixing  or  combining  with 
alumina,  and  the  compound  thus  produced  can  further 
combine  with  Alizarin  to  form  a  red-lake.  The  effect 
which  it  has  of  giving  brilliancy  and  fastness  to  the  ulti- 
mate colour  is  probably,  in  part  at  least,  due  to  its 
physical  action  of  enveloping  the  coloured  lake  with  a 
transparent  oily  varnish,  which  protects  it  more  or  less 
from  external  influences.  All  unchanged  oil  must  be  re- 
moved before  mordanting  (see  Operation  9). 

The  impregnation  of  the  cotton  with  tannin  matter 
fixes  an  additional  amount  of  alumina  on  the  fibre,  and 
tends  to  give  deeper  and  fuller  shades.  Its  use  is,  how- 
ever, by  no  means  absolutely  essential,  as  seemed  to  be 
the  case  when  Garancin  or  Madder  was  used,  and  by 
some  dyers  it  is  not  used. 

During  the  steeping  in  alum  solution  an  insoluble 
basic  aluminium  compound  is  formed  with  the  modified 
oil  and  also  with  the  tannic  acid  if  present.  The  com- 
plex mordant  thus  fixed  on  the  cloth  at  this  stage  combines 
with  Alizarin  in  the  subsequent  dye-bath  to  form  the 
Turkey-red  lake*    The  bullock/s  blood    used  is  said  to 


ANTHRACENE  COLOURING  MATTERS.  107 


prevent,  by  reason  of  the  coagulation  of  its  albumen, 
certain  impurities  accompanying  the  Alizarin  from  being 
fixed  on  the  cotton,  but  some  practical  Turkey-red  dyers 
say  that  blood-albumen,  glue,  and  other  substitutes  which 
have  been  tried,  cannot  entirely  replace  it.  It  certainly 
adds  brilliancy  and  purity  to  the  colour. 

The  "  first  clearing  ;;  operation  is  for  the  purpose  of 
removing  any  remaining  impurities  which  the  mordant 
may  have  attracted  in  the  dye-bath,  but  for  which  its 
affinity  is  far  less  than  for  Alizarin. 

The  "  second  clearing  ;?  is  said  by  some  to  introduce 
into  the  already  extremely  complex  coloured  lake  a  small 
portion  of  stannous  oxide.  Others  allege  that  there  is 
simply  a  tin-oleate  produced,  which  is  melted  and  spread 
over  the  fibre,  as  it  were,  without  entering  into  chemical 
combination  with  the  red-lake.  Liechti  has  proved  ana- 
lytically that  as  much  as  60  %  of  the  fatty  acid  of  the  soap 
employed  may  disappear  and  become  fixed  in  this  manner 
upon  the  fibre. 

The  practical  object  of  this  operation  is  to  give  the 
colour  the  maximum  purity  and  brilliancy  of  which  it  is 
capable. 

Steiner's  Process  for  Dyeing  500  kg.  =  9*8  cwt.  of 
Turkey-red  Cloth. — The  main  difference  between  this  and 
the  "  emulsion  process/'  already  described,  resides  in  the 
mode  of  applying  the  oil.  In  the  process  now  to  be 
described  the  cloth  is  impregnated  with  the  requisite 
amount  of  oil  at  one  operation,  namely,  by  padding  it  in 
clear  hot  oil  instead  of  in  an  oil-emulsion,  after  which 
it  receives  several  passages  through  weak  solutions  of 
alkaline  carbonate. 

This  method  is  capable  of  yielding  a  Turkey-red  dye 
of  exceptional  brilliancy  and  intensity — better,  indeed, 
than  it  is  possible  to  obtain  by  the  "  emulsion  process." 

1st  Operation :  Bleaching. — The  pieces  are  well  washed 
and  boiled,  during  2-3  hours,  with  water  ^nly;  then  boiled 
for  10-12  hours  with  22  litres  =  4'8  gals,  of  caustic  soda, 
70°  Tw.  (Sp  Gr.  1*35),  and  washed  :  then  boiled  a  second 
time,  for  10  hours,  with  16  litres  =  3*5  gals,  of  caustic 
soda,  70°  Tw.,  and  washed;  and  finally  steeped  for  2  hours 
in  sulphuric  acid,  2°  Tw.  (Sp.  Gr.  l'Ol),  well  washed  and 
dried. 


108  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


In  order  to  avoid  tendering  the  fibre  in  the  next  opera- 
tion, by  reason  of  traces  of  acid  left  in  the  cloth,  it  is 
padded  with  carbonate  of  soda  solution,  at  4°  Tw.  (Sp. 
Gr.  1*02),  and  then  dried. 

2nd  Operation:  Oiling.— The  cloth  is  padded  in  the 
open  width  in  olive  oil  maintained  at  a  constant  tempera- 
ture of  110°  C. 

Fig.  11  represents  a  section  of  the  oil-padding  machine 
of  Messrs.  Duncan  Stewart  &  Co.  It  consists  of  a  double- 
jacketed  tank  B  (inside  copper,  outside  iron)  for  contain- 


Fig\  11 — Oil-padding  Machine. 


ing  the  oil.  It  is  heated  by  means  of  steam,  and  is  pro- 
vided with  a  series  of  rollers  at  the  top  and  bottom. 
Above  is  a  pair  of  heavy  squeezing  rollers  c.  The  cloth  is 
passed  through  as  indicated  in  the  figure,  being  well 
opened  out  and  made  free  from  creases  before  entering 
the  oil,  by  means  of  the  straining  bars  AAA,  and  after- 
wards loosely  plaited  down  by  the  folder  D. 

After  padding,  the  cloth  is  detached  in  ten-piece  lengths 
and  hung  in  the  drying  stove,  the  temperature  of  which 
is  raised  as  rapidly  as  possible  to  70°  C,  and  this  is 
maintained  for  2  hours. 


ANTHRACENE   COLOURING  MATTERS.  109 


3rd  to  9th  Operation :  Liquoring. — Pad  the  cloth  seven 
times  in  the  open  width  through  a  solution  of  carbonate 
of  soda,  at  4°  Tw.,  and  hang  in  the  stove  after  each  pad- 
ding operation,  maintaining  the  temperature  in  each  case 
for  2  hours  at  75°-77°  C. 

In  winter  the  padding  liquors  are  made  warm 
(35°-40°  C),  but  in  summer  they  are  always  cold,  since 
if  too  hot,  oil  is  stripped  off  the  piece  to  an  excessive  and 
injurious  degree.  In  the  course  of  regular  working,  the 
liquors  soon  become  veritable  oil-emulsions,  and  constant 


Fig.  12. — Section  of  Liquor-padding-  Machine. 


oversight  is  necessary  in  order  to  maintain  their  specific 
gravity  as  constant  as  possible,  and  thus  ensure  ultimately 
a  regular  and  satisfactory  colour. 

A  section  of  the  liquor-padding  machine  of  Messrs. 
Duncan  Stewart  &  Co.  is  shown  in  Fig.  12.  It  consists 
of  a  wooden  box  or  tank  A  to  hold  the  liquor,  provided 
with  rollers  above  and  below.  Over  this  are  supported 
two  pairs  of  heavy  squeezing  rollers  b  c  and  D  E.  At  F 
a  few  straining  bars  serve  to  open  out  and  stretch  the 
cloth ;  G  is  the  folder.  The  mode  of  passing  the  pieces 
through  the  machine  is  readily  understood  from  the 
diagram. 

With  regard  to  the  stoving,  it  is  well  to  bear  in  mind 


110  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


that  during  the  first  stages  of  drying  much  vapour  is 
given  off,  and  special  attention  must  be  given  to  ensure 
adequate  ventilation.  Fig.  13  is  the  ground  plan,  show- 
ing heating  flues,  and  Fig.  14  is  a  sectional  elevation  of  a 
modern  four-storeyed  Turkey-red  stove.  A  A  represent  or- 
dinary coal  fires  situated  in  the  basement  ;  the  hot  flue-gases 


Fig-.  13.— Plan  of  Turkey-red  Stove. 


Fig.  14. — Sectional  Elevation  of  Turkey-red  Stove. 

pass  first  through  channels  made  of  fire-brick,  then  through 
iron  pipes,  and  finally  make  their  exit  to  the  chimney  at  b. 
The  upper  part  of  the  stove  is  divided,  by  floors  of  iron- 
grating,  into  several  storeys  c,  d,  e,  f,  each  of  which  is 
furnished  with  wooden  framework,  supporting,  one  above 
the  other,  two  pairs  of  horizontal  rails  provided  with 


ANTHRACENE   COLOURING  MATTERS.  Ill 


short,  upright,  wooden  pegs.  Over  these  pegs  one  selvedge 
of  the  cloth  is  firmly  hooked  alternately  from  right  to  left, 
while  the  other  is  allowed  to  hang  down ;  thus,  when  the 
stove  is  filled,  each  storey  is  closely  packed  with  two  tiers 
of  cloth  suspended  in  such  a  manner  that  the  heated  air 
from  below  can  readily  pass  between  each  fold. 

A  yarn  stove  is  similarly  constructed,  but  in  this  case 
the  ends  of  the  rods  holding  the  yarn  are  supported  on 
horizontal  rails  free  from  pegs. 

Another  mode  of  hanging  cloth,  but  one  which  is 
not  so  economical  of  space,  is  to  have  only  one  storey  in 
the  stove.  Above,  near  the  roof,  are  fixed  a  number  of 
strong,  smooth,  wooden  rails,  on  which  the  cloth  is  sus- 
pended in  long  folds,  reaching  down  to  within  one  or 
two  feet  of  the  iron  grating  immediately  above  the  hot 
flues. 

In  all  cases  efficient  ventilation  is  secured  by  means 
of  numerous  side  windows,  which  can  be  readily  opened 
and  closed  at  will. 

10th  Operation :  Steeping. — Run  the  cloth  in  the  open 
width  through  a  machine  consisting  of  a  large  vat  divided 
into  several  compartments  fitted  with  rollers  above  and 
below.  The  first  compartments  are  filled  with  a  solution  of 
carbonate  of  soda  at  J°  Tw.  (Sp.  Gr.  1  0025),  and  heated 
to  40°  C.    The  last  is  filled  with  water  only. 

The  cloth  is  then  well  washed,  and  dried  in  the  stove 
at  about  65°  C. 

11th  to  14th  Operation. — These  operations,  consisting  of 
mordanting,  dyeing,  and  clearing,  are  precisely  similar  to 
those  already  described  for  yarn-dyeing. 

It  may  be  well  to  state  that  the  number  of  paddings 
in  dilute  soda  solution  (liquoring)  varies  according  to  the 
quantity  of  oil  which  it  is  desired  to  fix  upon  the  cloth. 
Good  Turkey-red  contains  about  10  %  of  modified  oil  on 
the  fibre. 

"  Sulphated  Oil  Process"  for  Dyeing  500  kg.  =  9'8 
cwt.  of  Yarn  or  Cloth.— In  this  process  the  frequent 
repetitions  of  passing  the  fabric  through  oil-emulsions  or 
sodium  carbonate  and  then  stoving  are  not  used.  The 
olive  oil  is  replaced  by  an  alkaline  solution  of  sulphated 
olive  or  castor  oil,  with  which  only  a  single  impregnation 
is  necessary,  followed  by  a  steaming  or  stoving  process. 


112  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


1st  Operation :  Bleaching  or  Boiling. — This  is  identical 
with  that  already  given  in  describing  the  previous  pro- 
cesses for  yarn  and  cloth. 

2nd  Operation :  Preparing.  —  The  dry  cotton  is 
thoroughly  impregnated  by  "  tramping  "  or  "  padding  " 
with  a  cold  or  tepid  solution  of  10-15  kg.  =  22  0-33  0  lb. 
of  neutralised  sulphated-oil  (50  %)  per  100  litres  = 
22  0  gals,  of  water.  The  excess  is  removed,  and  the  cotton 
is  merely  dried  in  the  stove,  or  it  may  be  heated  for 
1-2  hours  at  75°  C. 

3rd  Operation:  Steaming. — The  prepared  and  dried 
cotton  is  submitted  to  the  action  of  steam,  2-5  lb.  pressure, 
during  1-lJ  hour. 

4th  Operation :  Mordanting. — The  cotton  is  worked  and 
steeped  for  2-4  hours  in  a  tepid  solution  of  commercial 
aluminium  acetate  (tin-red-liquor),  or  more  economically 
in  basic  aluminium  sulphate,  Al2(S04)o(0H)9,  at  8°  Tw. 
(Sp.  Gr.  T04). 

After  mordanting,  the  excess  of  aluminium  solution  is 
removed  by  wringing  or  hydro-extracting,  the  cotton  is 
dried,  and  then  either  simply  well  washed  in  cold  water 
or  first  worked  for  J  hour,  at  40°-50°  C,  in  a  chalk  bath 
containing  20-30  g.  =  308'6-462'9  grains  of  ground  chalk 
per  litre  (1  quart).  A  solution  of  sodium  phosphate  may 
replace  the  chalk  water.  Alkaline  fixing-agents  like  am- 
monia and  sodium  carbonate  are  best  avoided  in  case  any 
of  the  oil-preparation  should  be  stripped  off. 

bth  Operation :  Dyeing. — Dye  with  15-20  %  of  Alizarin 
(10  %),  with  the  addition  of  1  %  of  its  weight  of  chalk  or 
acetate  of  lime.  The  cotton  is  dyed  in  the  cold  for  \  hour 
to  ensure  regularity  of  colour,  the  temperature  is  then 
gradually  raised  to  70°  C.  in  the  course  of  1  hour,  and 
the  dyeing  is  continued  at  this  temperature  till  the  bath 
is  exhausted.  The  cotton  is  then  well  washed  (although 
with  highly  calcareous  water  this  is  best  omitted),  hydro- 
extracted,  and  dried. 

6th  Operation :  Second  Preparing. — The  dyed  and 
dried  cotton  is  again  impregnated  with  a  dilute  solution 
of  neutralised  sulphated  oil  (namely,  50-60  g.  =  77r6-925*9 
grains  of  sulphated  oil  [50  %]  per  litre),  and  then 
dried.  This  second  preparing  may  also  take  place 
after  the  mordanting,  the  oil  being  then  fixed  by  means 


ANTHRACENE  COLOURING  MATTERS. 


113 


of  a  second  mordanting  with  a  weak  solution  of  basic 
aluminium  sulphate,  etc. 

1th  Operation:  Second  Steaming. —The  dried  cotton 
is  steamed  as  before  for  1  hour. 

8th  and  9th  Operations :  First  and  Second  Clearing. — 
These  may  be  identical  with  operations  13  and  14,  described 
in  the  "  Emulsion  process/'  although  many  chemists  think 
that  soap  alone  should  be  used  here,  and  consider  that 
the  addition  of  stannous  chloride  is  altogether  unneces- 
sary if  not  irrational. 

The  "  sulphated-oil  process  "  is  comparatively  so  new 
that  numerous  slight  modifications  of  the  process  as  here 
given  are  naturally  tried  and  adopted  by  various  dyers, 
and  to  some  of  these  reference  will  now  be  made. 

The  sulphated-oil  used  is  invariably  carefully  neutral- 
ised, either  with  caustic  soda  or  ammonia.  As  a  rule, 
ammonia  is  preferred,  since  even  the  addition  of  an 
excess  of  ammonia  would  have  little  or  no  injurious  effect, 
owing  to  its  volatility ;  and  further,  the  ammonia  com- 
pound of  sulphated-oil  is  more  readily  decomposed  on 
steaming  than  the  sodium  compound,  and  a  more  com- 
plete fixing  of  the  oil  results.  Either  sulphated  castor  oil 
or  olive  oil  may  be  used.  Very  good  results  are  even 
obtained  by  the  simple  use  of  a  carefully  made  castor  oil 
soap,  which,  being  excessively  soluble,  and  giving  thin 
solutions,  is  well  fitted  to  impregnate  the  fibre  thoroughly. 

In  the  "  preparing  "  process,  the  cotton  does  not  at- 
tract or  fix  any  of  the  oil.  It  simply  absorbs  a  definite 
amount  of  the  solution,  and  supposing  sulphated  olive 
oil  to  have  been  used,  the  prepared  cotton  contains  the 
sodium  or  ammonium  compounds  of  oxyoleic  acid  and  of 
the  glycerine-sulphuric-ethers  of  oxyoleic  and  oxystearie 
acids,  these  being  its  constituent  elements.  It  is  very  im- 
portant to  know  the  exact  percentage  of  sulphated-oil  con- 
tained in  the  solution,  since  it  is  this  which  determines 
the  amount  of  oil  and  alumina  ultimately  fixed  on  the 
cotton,  and  consequently  the  beauty,  brilliancy,  and  fast- 
ness of  the  colour. 

According  to  Liechti  and  Suida,  the  action  of  the  first 
steaming  process  is  to  decompose  the  ammonium  or  sodium 
compounds  of  the  ether  constituent  of  sulphated  oil  into 
ammonium  or  sodium  sulphate,  glycerine,  oxyleic  and 


114  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


ANTHRACENE  COLOURING  MATTERS. 


115 


oxystearic  or  trioxyoleic  acid,  according  as  olive  or  castor 
oil  has  been  employed.  The  other  constituent  (oxyoleic  or 
trioxyoleic  acid)  remains  unchanged.  At  the  same  time 
the  steaming  causes  a  better  penetration  of  the  fibre  by 
these  oxidised  fatty  acids.  Sometimes  the  steaming  at  this 
stage  is  altogether  omitted.  The  decomposition  of  the  com- 
pound ether  referred  to  may  also  be  effected  by  heating 
the  dye-bath  to  the  boiling  point  instead  of  only  to  70°  C, 
the  bath  becomes  acid,  and  the  brilliancy  of  the  colour  is 
developed  suddenly. 

Fig.  15  represents  a  steaming-chest  for  yarn  made  by 
Messrs.  Tulpin  Frcres,  of  Rouen.  The  hanks  of  cotton 
are  suspended  on  square  wooden  rods  resting  on  an  iron 
skeleton  carriage  or  framework,  and  are  capable  of  being 
turned  during  the  steaming  process  to  ensure  every  por- 
tion being  efficiently  steamed.  The  iron  carriage  is  sup- 
ported on  wheels,  so  that  it  can  be  filled  with  yarn  and 
then  run  into  the  chest.  The  steaming-chest  itself  consists 
of  a  wrought-iron  horizontal  boiler,  with  a  movable  door 
at  one  end  provided  with  clamps.  For  the  prevention  of 
drops  there  is  fixed  internally  and  at  the  top  a  cover  of 
sheet  copper,  in  such  a  manner  as  to  leave  a  space  between 
it  and  the  boiler-plate.  The  chest  is  provided  with  a 
steam-gauge,  safety-valve,  and  blow-off  pipe.  The  steam 
enters  by  a  perforated  pipe  running  along  the  bottom  of 
the  boiler,  and  which  is  usually  covered  with  a  perforated 
iron  plate. 

Cotton  cloth  may  be  reeled  and  suspended  on  rods  in  a 
similar  way,  or  it  may  be  steamed  in  the  continuous 
steaming-chest  of  Messrs.  Duncan  Stewart  &  Co.,  Glasgow, 
represented  in  Figs.  16  and  17.  It  consists  of  an  annular- 
shaped  iron  cylinder  or  chamber  A  b,  in  the  upper  part  of 
which  a  series  of  brass  radial  rods  c  are  caused  to  circu- 
late slowly  by  means  of  the  endless  screw  E,  driven  by  the 
engine  D.  The  cloth  (in  the  open  width)  enters  the  annu- 
lar space  through  a  pair  of  squeezing  rollers  at  f.  By  an 
ingenious  arrangement  the  cloth,  which  is  suspended  in  long, 
loosely-hanging  folds  on  the  radial  rods,  is  carried  round 
the  annular  space,  and  makes  its  exit  by  a  second  pair  of 
squeezing  rollers  at  G.  The  chamber  is  constructed  of 
boiler-plate,  so  that  the  goods  can  be  submitted  to  high- 
pressure  steam.     Another  form  of  continuous  steaming- 


116  COLOURING  MATTERS  FOR  DYEING  TEXTILES- 


Fig.  16. — Elevation  of  Continuous  Steaming-Chcst. 


Fig.  17. — Plan  of  Continuous  Steaming-Chest. 


ANTHRACENE  COLOURING  MATTERS.  117 


machine  is  that  in  which  loose  rods,  supporting  the  cloth 
in  a  similar  manner,  are  passed  continuously,  by  means 
of  endless  chains,  through  a  large  rectangular  brick  cham- 
ber filled  with  very  low-pressure  steam. 

If  in  the  mordanting  process  the  cotton  was  merely 
dried  after  the  preparing  with  sulphated  oil,  there  are 
produced  upon  the  fibre  the  aluminium  compounds,  both 
of  the  ether  and  of  the  oxy-  or  trioxyoleic  acid ;  but  if  it 
was  also  steamed,  there  is  then  fixed  on  the  fibre  essentially 
the  normal  aluminium  compound  of  oxy-  or  trioxy-oleic 
acid  (Liechti  and  Suida). 

A  brighter  colour  is  obtained  by  adding  a  small  pro 
portion  of  stannous  chloride  to  the  aluminium  solution, 
or  stannate  of  soda  to  the  oil  solution. 

After  mordanting  and  washing,  a  slightly  basic  alu- 
minium salt  remains  on  the  fibre,  its  basic  character  being 
generally  caused  by  the  calcareous  condition  of  the  water. 
Traces  of  lime  are  also  present.  If,  previous  to  washing, 
a  warm  chalk  bath  is  used,  a  much  more  basic  and  more 
calcareous  aluminium  compound  is  formed. 

During  the  dyeing  process  there  is  probably  formed  the 
Alizarin  compound  of  the  basic  oxy-  or  trioxy-oleate  of 
aluminium  and  calcium  just  referred  to. 

If  there  is  a  deficiency  of  oil  on  the  fibre,  the  brightest 
shades  are  always  obtained  by  dyeing  at  the  low  tempera- 
ture indicated  (70°  C),  but  otherwise  the  temperature 
may  be  raised  to  the  boiling  point,  although  there  is  then 
a  tendency  of  a  portion  of  the  oily  mordant  being  softened 
and  boiled  out,  especially  if  it  is  in  slight  excess. 

With  the  use  of  pure  Alizarin — i.e.  the  "  blue  shade  of 
Alizarin/'  as  it  is  generally  called — a  fiery  brilliant  red 
is  not  obtained;  hence  such  as  contains  Isopurpurin  (An- 
thrapurpurin) — i.e.  the  "  yellow  shade  of  Alizarin  " — is 
generally  preferred. 

The  second  preparing  and  steaming  operations  have 
for  their  object  the  neutralising  of  the  basic  compound 
present  on  the  fibre  at  this  stage.  This  operation  of  steam- 
ing after  dyeing  has  a  most  remarkable  effect  in  giving 
brilliancy  and  fastness  to  the  colour,  especially  if  the  dye- 
ing has  been  conducted  at  a  low  temperature.  If  100°  C. 
was  employed,  then  the  brightening  effect  has  taken  place 
to  a  considerable  extent,  if  not  entirely,  already  in  the 


118  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


dye-bath,  as  above  mentioned.  Sometimes  the  second  pre- 
paring is  omitted,  and  a  small  quantity  of  neutralised 
sulphated  oil  is  added  to  the  dye-bath  instead. 

The  method  of  "  clearing  ??  described,  in  which  the 
cotton  remains  stationary  while  the  liquor  circulates 
through  it,  gives  very  much  better  results  than  if  the 
cotton  were  worked  vigorously  in  the  solution,  since  in 
this  latter  case  much  of  the  red-lake  would  be  mechanically 
removed  by  friction,  and  the  colour  would  look  poor  and 
weak. 

The  Action  of  Lime  Salts  in  the  Dye-bath. — One  of  the 
most  interesting  facts  connected  with  the  application  of 
Alizarin  is  the  necessity  of  the  presence  of  a  lime  salt  in 
the  dye-bath,  in  order  to  obtain  a  really  good,  serviceable 
colour.  The  general  result  of  researches  made  by  Schlum- 
berger,  Rosenstiehl,  and  others,  with  a  view  to  elucidate 
this  point,  seems  to  favour  the  idea  that  the  Alizarin-red 
lake,  as  fixed  upon  textile  fibres,  is  not  simply  an  alu- 
minium compound  of  Alizarin,  but  one  which  also  con- 
tains calcium  as  an  essential  constituent. 

The  following  results  of  Liechti  and  Suida's  researches 
bearing  on  this  point  will  explain  this.  Pure  aluminium 
hydrate,  whether  in  its  precipitated  form  or  fixed  on  the 
fibre,  cannot  be  properly  dyed  with  Alizarin  except  in  the 
presence  of  lime  compounds.  Normal  aluminium  phos- 
phate behaves  similarly.  Normal  aluminium  alizarate 
[A12(C]4HG04)3]  is  a  purplish-red  compound  soluble  in 
water,  alcohol,  and  ammonia.  Basic  aluminum  alizarates 
-e.g.  [Al2(014H6O,)(OH)J  and  [Al^C^H^XOH)^]- 
are,  on  the  contrary,  bright  red  compounds,  insoluble 
in  water  and  alcohol,  and  little  soluble  in  ammonia.  Alu- 
minium-calcium-alizarates  of  very  varied  composition, 
prepared  by  dyeing  aluminium  hydrate  with  Alizarin  in 
the  presence  of  calcium  acetate,  are  mostly  reddish-brown 
insoluble  compounds.  The  amount  of  lime  salt  present  in 
the  dj^e-bath  determines  the  quantity  of  Alizarin  which  will 
be  taken  up  by  the  alumina,  and  the  amount  of  lime  taken 
up  by  the  lake  is  determined  by  the  quantity  of  Alizarin 
employed.  The  relative  proportions  of  Alizarin,  alumina, 
lime,  and  fatty  acid  present  in  the  lake  abstracted  from 
Turkey-red  and  Alizarin-red-dyed  cotton,  vary  consider- 
ably, according  to  the  method  of  dyeing  employed;  as  a 


ANTHRACENE  COLOURING  MATTERS.  119 


rule,  a  large  excess  of  alumina,  in  proportion  to  the  lime 
and  Alizarin,  is  present.  The  above-mentioned  authors 
find  that  alumina-mordanted  cotton,  when  dyed  with 
Alizarin  in  the  presence  of  calcium  acetate,  takes  up  one- 
third  molecule  of  lime  for  each  molecule  of  AUzarin,  and 
they  consider  that  the  composition  of  the  lake  in  unsoaped 
Alizarin-red-dyed  cotton  is  best  expressed  by  the  formula 
[Ala0a(C14H6O4),(OH)a]. 

Another  Method  of  Dyeing  AUzarin  Red  on  cotton,  m 
use  among  calico-printers,  but  which  does  not  give  quite 
such  fast  colours  as  those  described  above,  is  given  in 
the  following  resume:  — 

1.  Mordant  with  commercial  aluminium  acetate,  5°-8° 
Tw.  (Sp.  Gr.  1  025-1  04),  dry,  and  age  for  1-2  days,  by 
hanging  in  a  chamber  heated  to  50°  C,  and  having  a 
somewhat  moist  atmosphere. 

During  this  "  ageing  7;  process  much  of  the  acetic  acid 
escapes,  and  alumina  or  a  basic  aluminium  acetate  is 
fixed  on  the  fibre. 

2.  Iu  order  to  fix  the  alumina  more  completely,  work 
the  cotton  for  a  few  minutes,  at  60°  C,  in  a  bath  of  phos- 
phate, arsenate,  or  silicate  of  soda,  5-10  g.  =  77  1-1543 
grains  per  litre  =  2  2  gals.  ;  then  wash  well  in  water. 

3.  Dye  with  Alizarin,  and  dry.  A  small  addition  of 
acetate  of  lime  is  used  if  necessary.  Since  the  cotton  at 
this  stage  contains  no  oil,  it  is  essential  to  the  obtaining 
of  a  bright  colour  that  the  dyeing  should  take  place  at  a 
temperature  not  exceeding  70°-75°  C. 

4.  Prepare  with  a  neutralised  solution  of  sulphated  oil 
50-100  g.  =  1-6-3-2  ozs.  (50  %)  per  litre  =  0  2  gal.,  and  dry. 

5.  Steam  for  i-f  hour  at  2  lb.  pressure. 

6.  Clear  as  before. 

Alizarin  Pinks,  Purples,  etc.,  on  Cotton. — Alizarin 
pinks  are  obtained  by  precisely  the  same  methods  as  are 
adopted  for  reds.  The  aluminium  mordant  employed 
must,  however,  be  considerably  weaker — use,  say,  alu- 
minium acetate  at  10°  Tw.  (Sp.  Gr.  1*05).  Basic  mordants 
are  avoided,  since  they  given  uneven  colours,  and  even 
normal  aluminium  sulphate  may  be  used  with  advantage ; 
the  amount  of  Alizarin  (20  %)  may  be  reduced  to  about 
1  %  of  the  weight  of  cotton,  and  the  proportion  of  oil 
preparation  required  is  correspondingly  diminished.  The 


120  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


most  pleasing  pinks  are  those  produced  by  using  a  "  blue 
shade  of  Alizarin/7  i.e.  one  free  from  Isopurpurin,  Flavo- 
purpurin,  or  Purpurin. 

Very  good  fast  shades  of  purple  and  lilac  are  obtained 
from  Alizarin,  either  with  or  without  the  use  of  oil 
preparation ;  indeed,  the  use  of  oil  does  not  seem  to  add 
any  particular  brilliancy  to  the  colour,  but  serves  mainly 
to  fix  the  mordant,  and  to  make  the  colour  a  little  faster 
to  boiling  soap  solutions. 
•  When  the  cotton  is  prepared  with  oil,  according  to 
either  the  Emulsion  or  Steiner's  process  for  Turkey-red, 
it  is  mordanted,  worked  and  steeped  for  a  short  time  in 
a  solution  of  ferrous  sulphate  at  3°-4°  Tw.  (Sp.  Gr.  1*015- 
102);  it  is  then  allowed  to  lie  over-night,  and  is  finally 
well  washed. 

The  amount  of  iron  precipitated  on  the  fibre,  and  of 
Alizarin  subsequently  taken  up  in  the  dye-bath,  is  deter- 
mined by  the  amount  of  oil  previously  fixed,  and  not 
merely  by  the  concentration  of  the  ferrous  sulphate  solu- 
tion. For  the  darker  shades  of  purple,  therefore,  the 
cotton  should  be  well  prepared  with  oil,  while  for  pale 
shades  the  preparation  is  slight.  The  best  and  bluest 
shades  are  only  obtained  when  the  mordant  is  thoroughly 
saturated  with  Alizarin ;  excess  of  uncombined  mordant 
gives  the  colour  an  unpleasant  dull-reddish  appearance. 

The  use  of  pyrolignite  of  iron  gives  somewhat  darker, 
brighter,  and  bluer  shades  than  the  sulphate.  Very  deep 
purplish  blacks  are  obtained,  and  with  less  oil  prepara- 
tion, by  steeping  the  cotton,  previous  to  mordanting,  in 
an  infusion  of  gall  nuts  or  other  tannin  matter. 

After  mordanting,  the  cotton  is  well  washed  and  dyed 
with  5-15  %  of  Alizarin  (10  %).  If  the  water  is  not 
sufficiently  calcareous,  it  is  very  essential  to  add  the  neces- 
sary quantity  of  chalk  or  acetate  of  lime  to  the  dye-bath 
(1-2  %).  After  dyeing,  the  cotton  should  be  washed  and 
soaped  at  a  temperature  of  60°  C. 

When  not  prepared  with  oil,  the  cotton  is  prepared 
with  tannin,  by  working  it  in  a  cold  infusion  of  tannin 
matter  (equal  to  1-2  g.  =  15"4-30*8  grains  of  tannic  acid 
per  litre  =  0  2  gal.)  ;  it  is  then  mordanted  in  a  solution  of 
pyrolignite  of  iron,  l°-3°  Tw  (Sp.  Gr.  1  005-1-015),  and 
finally  washed. 


ANTHRACENE  COLOURING  MATTERS.  121 


One  may  also  mordant  the  cotton  by  impregnating  it 
with  pyrolignite  of  iron,  l°-3°  Tw.,  wringing  out  the 
excess,  and  then  working  it  for  10  minutes,  at  50°  C.,  in 
a  solution  containing  20  cm3  =  12  cubic  inches  of  silicate 
of  soda,  16°  Tw.  (Sp.  Gr.  108)  per  litre  =  02  gal.,  and 
finally  washing  it.  Anthrapurpurin  gives  greyish  violets, 
Flavopurpurin  and  Purpurin  reddish  violets,  which  are 
little  esteemed. 

Various  shades  of  chocolate,  claret-red,  etc.,  are  ob- 
tained with  Alizarin  by  mordanting  the  oil-prepared 
cotton  with  a  mixture  of  aluminium  and  iron  mordants, 
either  in  the  state  of  sulphates  or  acetates.  Whether  the 
cotton  is  prepared  with  oil  according  to  the  Emulsion  or 
Steiner's  process,  or  by  the  sulphated  oil  method,  it  is 
advisable  to  work  it  in  a  weak  tannin  bath  before  mor- 
danting, especially  for  the  darker  and  bluer  shades, 
since  a  better  proportion  of  iron  is  fixed  by  this  means. 

The  different  shades  are  produced  by  varying  the  rela- 
tive proportions  of  aluminium  and  iron  mordant,  remem- 
bering always  to  vary  the  concentration  of  the  tannin  bath 
in  accordance  with  the  latter. 

After  mordanting,  the  cotton  is  washed,  dyed  with 
Alizarin,  prepared  with  weak  sulphated  oil,  steamed,  and 
soaped,  as  already  described. 

Certain  shades  of  claret-red  may  also  be  obtained  by 
mordanting  with  a  solution  of  chromium  acetate,  instead 
of  with  the  mixture  of  iron  and  aluminium  salts. 

Although  Alizarin  and  Anthrapurpurin  have  been 
mainly  alluded  to  in  the  above,  the  other  members  of  the 
anthracene  group — namely,  Flavopurpurin  and  Purpurin 
— may  be  applied  in  exactly  the  same  way,  and  give  rise 
to  similar  shades. 

Application  to  W ool. — Alizarin  is  capable  of  yielding 
a  number  of  pleasing  shades  on  wool,  according  to  the 
mordant  used,  and  ought  to  be  largely  employed  when- 
ever fastness  to  milling  and  to  light  is  required.  In 
conjunction  with  other  colouring  matters  which  are  simi- 
larly applied,  it  may  yield  an  endless  variety  of  shades. 
Its  application  presents  little  or  no  difficulty. 

To  obtain  Alizarin-red  on  wool,  mordant  the  wool  with 
6-10  %  of  aluminium  sulphate  (cake  alum)  and  5-8  % 
of  cream  of  tartar.    Introduce  the  wool  into  the  cold 


122  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


solution,  raise  the  temperature  gradually  to  the  boiling 
point  in  1  hour,  and  continue  boiling  \-\  hour.  Wash 
well,  and  dye  in  a  separate  bath,  with  10  %  of  Alizarin 
(20  %)  and  4-6  %  of  acetate  of  lime  (solid).  In  order  to 
ensure  an  even  colour  it  is  well  to  work  the  wool  for 
J  hour  in  the  cold  d37e-liquor,  then  to  raise  the  temperature 
gradually,  in  the  course  of  1  hour,  to  the  boiling  point, 
and  boil  \  hour,  or  till  the  bath  is  exhausted.  After  dye- 
ing, wash  well,  and  dry  at  a  low  temperature  or  in  the 
open  air. 

The  addition  of  cream  of  tartar  to  the  mordanting 
bath  is  absolutely  essential  to  the  production  of  a  full 
rich  colour.  Excess  of  tartar  tends  to  give  intensity,  but 
diminishes  the  brilliancy  of  the  colour.  Care  must  be 
taken  that  the  aluminium  sulphate  used  is  free  from  iron. 
With  a  deficiency  of  mordant  the  colour  lacks  brilliancy 
and  intensity,  and  if  the  deficiency  is  excessive  only  a 
poor,  dull  brick-red  is  obtained.  With  excess  of  mordant 
the  colour  tends  to  become  yellower  and  less  intense, 
Brighter  and  more  orange  shades  are  obtained  by  using, 
along  ,  with  the  aluminium  sulphate,  1-4  %  of  stannous 
chloride,  in  which  case  a  further  addition  of  1-4  %  of 
cream  of  tartar  is  necessary. 

The  addition  to  the  dye-bath  of  acetate  of  lime  (or  an 
equivalent  amount  of  ground  chalk)  is  also  absolutely 
necessary  if  the  water  employed  is  not  sufficiently  calcar- 
eous. Without  lime,  the  colour  is  poor  and  worthless,  and 
the  dye-bath  is  not  exhausted ;  with  excess,  the  red  is 
darker  and  duller. 

On  comparing  the  colours  given  by  the  various  mem- 
bers of  the  Alizarin  family  of  colouring  matters,  it  is 
found  that  Alizarin  itself  yields  a  very  blue  shade  of  red, 
or  a  claret-red;  Anthrapurpurin,  a  bright  red;  Flavo- 
purpurin,  a  somewhat  duller  and  yellower  red;  Purpurin, 
a  shade  approaching  that  given  by  Alizarin,  but  much 
yellower,  namely,  a  dull  brownish-red. 

To  obtain  Alizarin-orange  on  wool,  mordant  the  wool 
with  5-8  %  of  stannous  chloride  (tin-crystals)  and  an  equal 
weight  of  cream  of  tartar.  Dye  with  10  %  of  Alizarin 
(20  %)  without  the  addition  of  acetate  of  lime.  With  the 
addition  of  4-5  %  of  acetate  of  lime  a  bright  orange-red  is 
obtained,  but  without,  the  colour  is  very  much  yellower. 


ANTHRACENE  COLOURING  MATTERS.  123 


Excess  of  lime  makes  the  orange  still  redder,  but  it  is  apt 
to  be  uneven.  Alizarin-orange  may  also  be  dyed  in  a 
single  bath.  Alizarin  gives  a  bright  reddish  orange ; 
Flavopurpurin  a  bright  yellowish-orange.  The  colour 
yielded  by  Anthrapurpurin  holds  an  intermediate  place ; 
it  is  a  bright  orange;  Purpurin  gives  a  moderately  bright 
orange-red. 

Very  rich  claret-brown  shades  are  obtained  by  mor- 
danting the  wool  with  3  %  of  bichromate  of  potash  and 
1  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  T84).  The  addi- 
tion of  the  sulphuric  acid  is  beneficial,  since  it  tends  to 
give  a  somewhat  yellower  and  fuller  colour;  it  is  not, 
however,  absolutely  essential.  Dye  with  10  %  of  Alizarin 
(20  %).  The  addition  of  2-4  %  of  acetate  of  lime  to  the 
dye-bath  makes  the  colour  somewhat  less  yellow,  or  bluer, 
though  apparently  slightly  less  intense.  Strange  to  say, 
its  addition  is  by  no  means  essential,  as  in  the  case  of  the 
aluminium  mordant  for  dyeing  reds.  Good  colours  are 
also  obtained  by  the  single-bath  method ;  use  1  %  K2Cr207 
and  1  %  H2S04,  168°  Tw.  Numerous  fast  shades  of  brown, 
olive,  purple,  etc.,  are  obtained  by  associating  Alizarin 
with  such  colouring  matters  as  Galle'in,  Coerulein,  and 
many  of  the  dyewoods. 

The  shades  yielded  by  the  different  members  of  the 
Alizarin  group  with  chromium  mordant  are  as  follows  : 
Alizarin  gives  a  dull  purple  colour;  Anthrapurpurin,  a 
much  redder  shade,  namely,  a  claret-brown ;  Flavopur- 
purin, a  yellower  shade  of  claret-brown ;  Purpurin  gives 
the  most  intense  colour  of  all,  namely,  a  deep  claret- 
brown. 

Very  good  shades,  ranging  from  bluish-violet  to  slate, 
are  obtained  by  mordanting  wool  with  4-8  %  ferrous  sul- 
phate and  4-8  %  cream  of  tartar,  and  dyeing  in  a  separate 
bath  with  10  %  Alizarin  (20  %)  and  5  %  carbonate  of  lime. 
With  the  single-bath  method  darker  colours  are  obtained, 
but  they  are  much  browner  and  duller ;  use  6  %  ferrous 
sulphate  and  0'6  %  oxalate  of  potash.  Iron-alum  em- 
ployed instead  of  ferrous  sulphate  gives  good  results. 

Copper  sulphate  as  the  mordant  gives  claret-browns, 
either  by  the  mordanting  and  dyeing  method  or  by  the 
single-bath  method. 

With  the  use  of  ammoniacal  sulphate  of  nickel  and 


124  COLOURING  MATTERS  FOR  DYEING  TEXTILES 


uranium  salts,  as  mordants,  Alizarin  yields  nice  shades  of 
grey  and  slate. 

Application  to  Silk. — Alizarin  is  little  used  in  silk- 
dyeing.  Good  colours  may  be  obtained  by  mordanting 
the  silk  according  to  the  ordinary  methods,  and  working 
it,  after  dyeing,  in  hot  soap  solution. 

Nit  ro- Alizarin  [C1,,H5-N02,(OH)2].  —  This  colouring 
matter,  also  called  Alizarin  Orange,  is  produced  by  the 
action  of  nitrous  acid  on  Alizarin.  It  is  applied  to  the 
various  fibres  in  the  same  way  as  Alizarin :  although  it 
yields  fast  colours,  it  finds  as  yet  only  a  comparatively 
limited  employment. 

Application  to  Wool. — With  aluminium  mordant  it 
yields  very  good  orange  colours.  Mordant  the  wool  with 
6-8  %  of  aluminium  sulphate  and  7-9  %  of  cream  of  tartar. 
Excess  of  mordant  renders  the  shade  dull.  The  addition 
of  acetate  of  lime  to  the  dye-bath  makes  the  colour 
browner. 

With  stannous  chloride  mordant  the  colour  obtained 
varies  very  considerably,  according  to  the  amount  of  mor- 
dant employed.  W"ith  a  small  amount  (1  %  of  stannous 
chloride  and  1*5  %  of  cream  of  tartar),  a  very  reddish- 
orange  is  obtained ;  with  double  the  amount,  the  colour 
becomes  a  yellowish-orange ;  with  4  %  of  stannous  chloride, 
only  a  dull  brown  is  obtained,  the  normal  colour  being 
evidently  destroyed  by  the  reducing  action  of  an  excess 
of  mordant.  The  addition  of  acetate  of  lime  to  the  dye- 
bath  is  not  beneficial,  since  the  yellowish-orange  colour 
is  thereby  changed  to  brown. 

With  stannic  chloride  (equivalent  to  6  %  stannous 
chloride,  SnCl2'2H20)  an  orange  colour  is  also  obtained. 
Excess  of  mordant  does  not  destroy  the  colour  as  in  the 
case  of  stannous  chloride. 

With  copper  sulphate  mordant  a  very  good  brownish- 
red  is  obtained.  Use  4-6  %  of  copper  sulphate,  without 
calcium  acetate. 

With  ferrous  sulphate  as  the  mordant  a  purplish- 
brown  is  obtained.  Use  6-8  %  of  ferrous  sulphate,  without 
calcium  acetate  in  the  dye-bath. 

Bichromate  of  potash  as  the  mordant  yields 
brownish-reds.  Use  3  %  of  potassium  dichromate  and 
2  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84).  When 


ANTHRACENE  COLOURING  MATTERS.  125 


potassium  dichromate  alone  is  employed,  the  colour 
becomes  darker  with  increase  of  mordant,  even  till  16  % 
be  employed. 

Alizarin,  Blue  [C17H9NOJ. — This  colouring  matter, 
also  called  Anthracene  Blue,  is  derived  from  Nitro- 
Alizarin  by  heating  it  with  glycerine  and  sulphuric  acid. 
It  may  be  considered  as  the  quinolin  of  Alizarin,  and 
has  in  consequence  both  basic  and  acid  properties.  It  is 
met  with  in  commerce  in  two  forms,  namely,  as  a  paste 
containing  about  10  %  of  dry  substance,  and  as  a  powder 
under  the  name  of  Alizarin  Blue  S.  The  former  is  in- 
soluble in  water,  although  certain  commercial  marks 
(WX,  WR)  possess  some  degree  of  solubility.  The  latter, 
which  is,  indeed,  a  sodium  disulphite  compound  of 
Alizarin  Blue  (C17H0NO4"2NaHSO3),  is  readily  soluble  in 
water,  with  a  brownish-red  colour.  Its  solutions  decom- 
pose, if  heated  to  70°  C,  with  precipitation  of  the  in- 
soluble form  of  blue.  With  lime  it  forms  an  insoluble 
compound;  hence  the  presence  of  lime  salts  in  the  dye-bath 
must  be  avoided,  otherwise  there  will  be  a  loss  of  colour- 
ing matter. 

The  insoluble  form  of  Alizarin  Blue  may  be  applied  in 
dyeing,  according  to  the  indigo-vat  method,  by  reducing 
it  with  zinc  powder  and  carbonate  of  soda,  or  by  the 
ordinary  method  of  mordanting  and  dyeing  in  separate 
baths.  When  the  latter  method  is  employed,  a  certain 
proportion  of  disulphite  of  soda  may  be  added  to  the 
dye-bath  to  render  it  soluble,  or  the  dyeing  at  100°  C. 
must  be  long  continued.  Avoid  the  use  of  copper  dye- 
vessels. 

With  Alizarin  Blue  S  the  mordanting  and  dyeing 
method  only  is  employed. 

Application  to  Cotton. — Mordant  the  cotton  with 
chromium  according  to  the  alkaline  method.  Dye  in  a 
separate  bath  with  Alizarin  Blue ;  raise  the  temperature 
gradually  to  the  boiling  point  in  the  course  of  \\  hours, 
and  continue  boiling  for  \  hour. 

Application  to  Wool. — The  most  suitable  mordant  to 
employ  is  bichromate  of  potash,  in  the  proportion  of  3-6  % 
of  the  weight  of  wool.  The  addition  of  sulphuric  acid, 
168°  Tw.  ($p.  Gr.  1*84),  is  not  beneficial  if  used  in  larger 
amount  than  1  %.    Dye  in  a  separate  bath  with  Alizarin 


126  .COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Blue ;  raise  the  temperature  gradually  to  the  boiling  point, 
and  continue  boiling  until  a  bright  pure  shade  is  ob- 
tained. With  insufficient  boiling  the  colouring  matter  is 
only  superficially  attached  to  the  fibre.  The  colour  ob- 
tained is  a  bright  indigo-blue,  with  purplish  bloom.  It 
is  exceedingly  fast  to  scouring,  milling,  light,  etc.,  and 
has  the  advantage  of  not  rubbing  off. 

When  aluminium,  sulphate  is  the  mordant  employed 
a  purplish-blue  is  obtained,  which  is  very  liable  to  be 
uneven  unless  great  care  is  taken.  Use  6-8  %  of  alu- 
minium sulphate  and  5-7  %  of  cream  of  tartar. 

With  stannous  chloride  mordant  a  much  redder  purple 
is  obtained.  Use  4  %  of  stannous  chloride  (crystals)  and 
2  %  of  cream  of  tartar.  This  mordant  is  not  suitable  for 
employing  alone. 

Ferrous  sulphate,  as  a  mordant  for  Alizarin  Blue,  is 
also  little  suitable.  It  gives  a  greenish-blue  colour,  pos- 
sessing little  brilliancy,  and  apt  to  be  uneven.  Mordant 
with  4  %  ferrous  sulphate  and  8  %  cream  of  tartar. 

Application  to  Silk. — Mordant  the  silk  with  alumi- 
nium or  iron  in  the  usual  manner ;  wash  and  dye  in  a 
separate  bath  with  Alizarin  Blue.  Brighten  the  colour 
afterwards  by  boiling  the  silk  in  a  soap  bath. 


127 


CHAPTER  VIII. 

CHROME    YELLOW — IRON    BUFF — MANGANESE    BROWN — 
PRUSSIAN  BLUE. 

The  mineral  colouring  matters  applied  in  dyeing  arc 
extremely  limited,  and  they  are  almost  entirely  confined 
to  the  vegetable  fibres,  the  most  notable  exception  in  this 
respect  being  Prussian  Blue,  and  this,  strictly  speaking, 
is  not  a  mineral  colouring  matter. 

Chrome  Yellow. — Reference  has  already  been  made  to 
the  production  of  this  colour  in  describing  the  application 
of  bichromate  of  potash  and  of  lead  salts  to  the  cotton 
fibre.  In  addition  to  the  methods  there  indicated,  the 
following,  specially  intended  for  orange,  may  be  used  : — 

Prepare  a  bath  of  plumbate  of  lime  by  adding  a  solu- 
tion of  15-25  kg.  =  33*0-550  lb.  of  pyrolignite  of  lead  to 
milk  of  lime  containing  20-30  kg.  =  44*0-66' 1  lb.  of  lime, 
and  500  litres  =  110  0  gals,  of  water.  The  mixture  is  well 
agitated,  and  then  allowed  to  settle  for  about  2  hours. 

The  cotton  is  worked,  and  steeped  in  the  more  or  less 
milky  supernatant  liquid  for  1-2  hours,  then  squeezed  and 
washed.  Dye  in  a  cold  or  tepid  (40°-50°  C.)  solution  con- 
taining 5  %  of  bichromate  of  potash,  and  \-l  %  of  sul- 
phuric acid,  168°  Tw.  (Sp.  Gr.  1*84).  Wash,  and  develop 
the  orange  colour  by  passing  the  cotton  into  clear,  boiling 
lime-water,  then  wash  and  dry.  The  cotton  must  be  re- 
moved from  the  lime-water  bath  whenever  the  full  orange 
colour  is  developed,  otherwise  the  colour  loses  brilliancy. 

Iron  Buff. — This  colour  simply  consists  of  ferric  oxide. 
It  is  produced  by  first  impregnating  the  cotton  with  a 
ferrous  salt  solution,  then  passing  it  through  an  alkaline 
solution,  to  precipitate  ferrous  hydrate;  the  latter  is  then 
changed  into  ferric  hydrate  by  simple  exposure  to  the  air, 
or,  preferably,  by  passing  the  cotton  into  a  cold  dilute 
solution  of  bleaching-powder. 

Instead  uf  a  ferrous  salt,  one  may  also  employ  a  ferric 
salt,  as  ferric  sulphate  or  nitrate.    The  cotton  is  simply 


128  COLOURING  MATTERS  FOR  DYEING  TEXTILES, 


impregnated  with  the  ferric  solution,  then  squeezed,  and 
passed  rapidly  through  a  dilute  solution  of  carbonate  of 
soda,  ammonia,  or  milk  of  lime.  In  this  case,  ferric 
hydrate  is  at  once  precipitated  on  the  fibre,  and  no  subse- 
quent oxidation  is  necessary. 

Iron  Buffs  are  very  fast  to  light  and  boiling  alkaline 
solutions,  but  are  sensitive  to  the  action  of  acids. 

Manganese  Brown. — The  production  of  this  colour  on 
cotton  has  been  already  briefly  described ;  it  is  exactly 
analogous  to  the  production  of  Iron  Buff  from  ferrous 
salts.  The  process  is  simplified  by  adding  a  little  sodium 
hypochlorite  to  a  solution  of  caustic  soda,  passing  the 
cotton  impregnated  with  manganous  chloride  at  once 
through  this  mixture.  In  this  case,  precipitation  and 
oxidation  take  place  simultaneously. 

It  is  very  important  always  to  use  caustic  soda  free 
from  carbonate,  otherwise  a  little  manganous  carbonate 
is  precipitated  on  the  fibre,  and  since  this  compound  does 
not  oxidise  readily,  the  colour  is  apt  to  be  irregular. 

According  to  A.  Endler,  irregularity  of  colour  may 
also  arise  from  the  unsuitable  physical  properties  of  the 
precipitate  itself,  when  it  is  produced  in  the  ordinary 
manner  described.  Endler  obviates  these  defects  by  pass- 
ing the  cotton,  after  impregnation  with  manganous 
chloride,  into  a  bath  containing  25  litres  ==  5*5  gals,  of 
water,  7  litres  =  1*5  gals,  of  ammonia,  and  500  g.  = 
1*6  ozs.  of  bichromate  of  potash.  A  somewhat  unstable 
chromate  of  manganese  is  formed  on  the  fibre,  which,  on 
decomposing,  allows  the  chromic  acid  to  react  on  the 
manganous  hydrate  and  change  it  into  some  higher  state 
of  oxidation.  A  final  passage  in  dilute  bleaching-powder 
solution  completes  the  process. 

Manganese  Brown  is  very  fast  to  the  action  of  light, 
alkalis,  and  acids. 

Prussian  Blue:  Application  to  Cotton. — Prussian  Blue 
was  formerly  very  much  dyed  upon  cotton.  Since  the 
introduction  of  Aniline  blues  it  has  been  much  less  em- 
ployed. 

The  cotton  is  first  dyed  an  Iron  Buff,  and  is  then  dyed 
in  a  cold  solution  of  potassium  ferrocyanide,  20  g.  = 
308'6  grains  per  litre,  with  the  addition  of  10  g.  —  154'3 
grains  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84X  Wash 


PRUSSIAN  BLUE. 


129 


and  dry.  The  intensity  of  the  blue  depends  upon  the 
quantity  of  ferric  oxide  fixed  upon  the  fibre  in  dyeing 
the  buff. 

Fine  purplish  shades  of  blue  are  obtained  by  working 
the  cotton  at  30°  C.  in  nitro-sulphate  of  iron  at  5°  Tw. 
(Sp.  Gr.  1*025),  to  which  2-3  %  of  stannous  chloride  has 
been  added,  and  then  dyeing  in  a  cold  acidified  solution 
of  potassium  ferrocyanide.  Wash  and  dry;  or,  if  a  still 
more  purplish  tone  of  colour  is  required,  work  for  a 
short  time  in  a  tepid  bath  containing  Methyl  Violet  or 
Logwood  liquor. 

Alkaline  or  boiling  soap  solutions  readily  decompose 
Prussian  Blue,  leaving  brown  ferric  oxide  on  the  fibre. 
Prolonged  exposure  to  sunlight  causes  the  blue  to  fade, 
but  it  is  restored  if  kept  for  some  time  in  the  dark. 

Application  to  W ool. — Prussian  Blues  (sometimes  also 
called  Royal  Blues)  are  obtained  on  wool  by  means  of 
red  and  yellow  prussiate  of  potash,  i.e.  potassium  ferri- 
and  ferrocyanide.    The  former  gives  the  best  results. 

The  method  depends  upon  the  fact  that  when  a  mineral 
acid  is  added  to  solutions  of  either  of  these  salts  the 
corresponding  hydro-ferri-  or  hydro-ferrocyanic  acids  are 
liberated,  and  these,  under  the  influence  of  heat  and  by 
oxidation,  decompose  and  produce  insoluble  Prussian 
Blue.  If,  then,  wool  is  boiled  in  an  acidified  solution  of 
these  salts,  the  liberated  acids  are  taken  up  by  the  wool, 
decomposition  takes  place  gradually,  and  Prussian  Blue 
is  precipitated,  and  becomes  fixed  on  the  wool. 

The  wool  is  introduced  into  a  cold  bath  containing  a 
solution  of  10  %  of  red  prussiate  of  potash,  and  20  %  of 
sulphuric  acid,  at  168°  Tw.  (Sp.  Gr.  1*84) ;  the  tempera- 
ture is  gradually  raised  in  the  course  of  1  hour  to  100°  C., 
and  this  temperature  is  maintained  for  J-f  hour. 

The  colour  is  rendered  brighter  and  more  purplish  by 
adding  1-2  %  of  stannous  chloride  during  the  last  J-j 
hour  of  the  boiling. 

Although  sulphuric  acid  gives  the  best  result,  one 
may  also  use  nitric  or  hydrochloric  acid,  in  which  case 
the  shade  of  blue  is  modified  slightly.  Nitric  acid,  for 
example,  makes  the  shade  greener.  It  is  very  usual  with 
dyers  to  employ  a  mixture  of  all  three  acids,  especially 
when  yellow  prussiate  of  potash  is  employed.  This  mix- 
I 


130  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


ture  of  acids,  which  is  called  "  royal  blue  spirits,"  or 
merely  "  blue  spirits/7  may  vary  slightly  in  composition 
with  different  dyers.  A  usual  mixture  is  the  following  : 
4  measures  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84); 
2  measures  of  hydrochloric  acid,  32°  Tw.  (Sp.  Gr.  1'16) ; 
and  1-2  measures  of  nitric  acid,  64°  Tw.  (Sp.  Gr.  1'32). 

When  yellow  prussiate  of  potash  is  employed,  the  use 
of  nitric  acid  gives  the  best  result,  probably  by  reason 
of  its  oxidising  action.  For  10  %  of  yellow  prussiate  of 
potash  use  8-12  %  of  nitric  acid,  64°  Tw. 

Instead  of  stannous  chloride  in  the  crystalline  state, 
the  dyer  generally  uses  it  in  solution,  as  "  muriate  of  tin." 
It  is  often  sold  to  the  dyer  as  "  finishing  blue  spirits," 
though  under  this  name  it  generally  contains  a  slight 
addition  of  sulphuric  or  oxalic  acid,  or  both.  These 
additions,  however,  are  not  essential. 

Another  method  of  dyeing  Prussian  Blue,  but  one  now 
seldom  employed,  is  the  following  : — 

The  wool  is  worked  for  2  hours,  at  30°  C,  in  a  solution 
of  ferric  sulphate,  2°  Tw.  (Sp.  Gr.  101),  containing 
2-3  %  of  stannous  chloride,  and  2-8  %  of  cream  of  tartar. 
The  material  is  then  well  washed,  and  worked  for  2-3 
hours,  at  80°-90°  C,  in  a  bath  containing  1  %  of  yellow 
prussiate  of  potash,  and  4  %  of  oxalic  acid,  or  sulphuric 
acid,  168°  Tw.  (Sp.  Gr.  184). 

In  the  first  bath  there  is  fixed  on  the  wool  ferric 
oxide,  which  combines  with  the  free  hydro-ferrocyanic 
acid  contained  in  the  second  bath.  The  depth  of  blue  is 
regulated  by  the  strength  of  the  ferric  sulphate  solution, 
and  the  amount  of  yellow  prussiate  in  the  second  bath 
should  correspond  to  the  amount  of  ferric  oxide  fixed 
upon  the  wool. 

Application  to  Silk.— Prussian  Blue  is  now  seldom  dyed 
on  silk,  except  as  a  groundwork  for  black. 

What  was  formerly  known  as  Raymond's  Blue  was 
dyed  as  follows  : — 

'  Work  the  silk  in  basic  ferric  sulphate  (nitrate  of  iron), 
5°  Tw.  (Sp.  Gr.  1  025),  for  J  hour,  wring  out,  and  let 
it  lie  over-night.  Wash  well,  and  work  for  J  hour  in  a 
boiling  soap  bath  containing  about  10  %  of  soap ;  wash, 
and  dye,  at  40°-50°  C,  for  |-|  hour  in  a  fresh  bath  con- 
taining 9  %  of  yellow  prussiate  of  potash,  and  12  %  of 


PRUSSIAN  BLUE. 


131 


hydrochloric  acid,  32°  Tw.  (Sp.  Gr.  1*16),  and  finally  wash 
well. 

So-called  "  Napoleon's  Blue  "  is  a  brighter  blue,  pro- 
duced as  follows  : — 

Work  for  \  hour  in  a  cold  bath  containing  50  %  of 
basic  ferric  sulphate,  50°  Tw.  (Sp.  Gr.  1*25),  10  %  of 
stannous  chloride,  and  5  %  of  sulphuric  acid,  168°  Tw. 
(Sp.  Gr.  1'84);  wring  out,  wash,  and  work  for  J  hour,  at 
40°  C.,  in  a  second  bath  containing  10  %  of  yellow  prus- 
siate  of  potash,  2-h  %  of  red  prussiate  of  potash,  and 
12-15  %  of  sulphuric  acid,  168°  Tw.  (Sp.  Gr.  1*84).  After 
wringing  out  from  this  second  bath,  the  whole  process  is 
repeated.  Previous  to  drying,  the  silk  is  softened  and 
brightened  by  working  it  for  \  hour  in  a  cold  bath  con- 
taining an  imperfectly  made  sulphated  oil.  For  1  kg.  of 
silk,  use  a  mixture  of  150  g.  =  1314  6  grains  of  olive  oil 
and  15  g.  =  231*4  grains  of  sulphuric  acid,  168°  Tw.  (Sp. 
Gr.  1-84). 


132 


CHAPTER  IX. 

METHOD   OF   DEVISING  EXPERIMENTS   IN  DYEING. 

Experiments  with  Catechu. — In  the  present  chapter  it  is 
intended  to  give  some  idea  of  the  manner  in  which  the 
intelligent  textile  colourist  proceeds,  in  order  to  discover 
the  best  methods  of  applying  colouring  matters  to  textile 
fibres. 

As  an  interesting  example,  the  fixing  of  Catechu  on 
cotton  may  be  taken  : — 

First  of  all,  the  solubility  of  the  colouring  matter  in 
ordinary  solvents  should  be  determined-  in  water,  in 
acetic  acid,  in  alkalis,  etc.  The  behaviour  of  the  solu- 
tions towards  ordinary  practically  useful  reagents  should 
then  be  ascertained. 

An  aqueous  solution  of  Catechu  thus  tested  would, 
for  example,  show  the  following  properties  : — 

Gelatin  gives  a  voluminous  reddish-coloured  precipi- 
tate. 

Alkalis  give  the  solution  a  brownish  coloration. 
Lime-water  gives  a  yellowish  coloration,  and  a  pre- 
cipitate. 

Aluminium  salts  cause  the  solution  to  become  lighter- 
coloured  and  yellowish. 

Ferrous  salts  impart  an  olive-green  coloration. 

Ferric  salts  impart  a  dark-green  coloration. 

Copper  sulphate  gives  an  olive  coloration. 

Copper  acetate  gives  a  copious  dark-brown  precipitate. 

Lead  salts  give  a  yellowish-grey  precipitate. 

Potassium  dichromate  gives  a  copious  brown  precipi- 
tate ;  etc.  etc. 

If  a  piece  of  calico  is  impregnated  with  an  aqueous 
solution  of  Catechu,  then  dried,  and  at  once  washed,  most 
of  the  colouring  matter  will  be  removed;  if,  however, 
previous  to  washing,  it  is  allowed  to  hang  for  a 
lengthened  period,  or,  better  still,  if  it  is  steamed,  it 
will  be  observed  that  a  portion  of  the  colouring  matter 


EXPERIMENTS  IN  DYEING. 


133 


will  become  oxidised  and  thus  fixed  on  the  fibre.  This 
takes  place  still  more  largely  if  a  weak  alkaline  solution 
of  Catechu  be  employed,  or  if  some  oxidising  agents — as 
certain  copper  salts — be  added  to  the  aqueous  solution. 
The  best  results,  however,  are  obtained  by  passing  the 
steamed  calico  through  a  solution  of  potassium  dichromate, 
a  fact  which  was  already  indicated  by  the  result  obtained 
in  the  last-mentioned  of  the  examinations  in  the  test-tube. 
Greenish  tones  of  colour  are  obtained  by  passing  the  cloth 
afterwards  into  iron  solutions,  or  by  padding  the  white 
calico  in  an  acetic  acid  solution  of  Catechu  containing 
ferrous  sulphate,  drying,  and  steaming.  If  in  this  last 
case  the  steamed  calico  be  further  passed  into  potassium 
dichromate  solution,  the  colour  is  greatly  developed  in 
intensity,  and  becomes  browner. 

From  the  foregoing  preliminary  experiments,  the 
method  of  applying  Catechu  to  calico  might  be  formulated 
as  follows  :  Pad  the  cotton  in  an  aqueous,  alkaline,  or 
acetic  acid  solution  of  Catechu,  dry,  age,  steam,  pass 
through  a  solution  of  potassium  dichromate,  and  wash, 
if  brown  tones  of  colour  are  required.  For  obtaining 
greenish  tones,  the  method  to  be  adopted  would  be  to  pass 
the  calico,  after  steaming,  through  iron  solutions,  or  to 
add  ferrous  sulphate  to  the  padding  solution. 

But,  however  interesting  the  observations  just  recorded 
may  be,  only  a  very  small  portion  of  the  problem  has  thus 
been  solved;  the  question  still  remains,  what  relative  and 
absolute  proportions  of  the  various  ingredients  should  be 
employed,  in  order  to  obtain  the  most  satisfactory  result  ? 
Further,  what  are  the  best  conditions  under  which  the 
several  substances  must  be  applied,  as  regards  temperature 
of  solutions,  duration  of  steeping,  steaming,  exposure  to 
air,  etc. 

To  answer  these  questions,  another  series  of  experi- 
ments is  necessary.  Several  solutions  are  made,  contain- 
ing 25,  50,  100  g.  =  385  7,  771'6,  1543-2  grains  of  Catechu 
per  litre  of  hot  water,  in  each  of  which  a  "  swatch," 
"  fent,"  or  "  sample  "  of  calico  of  suitable  size  is  padded, 
then  dried,  and  steamed.  In  a  similar  manner  several 
solutions  of  potassium  dichromate  are  made,  containing, 
say,  5,  10,  20  g.  =  77*2,  154'3,  308*6  grains  of  K2Cr207  per 
litre  =  0*2  gal.,  and  portions  of  each  padded  sample  are 


134  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


passed  into  each  dichromate  solution,  for,  say,  2  minutes 
at  the  ordinary  temperature.  Similar  portions  are  passed 
through  identical  solutions  at  a  medium  temperature, 
say  50°  C,  and  others  again  at  the  boiling  point. 

The  experiments  can  be  further  extended  by  substitut- 
ing alkaline  chromate  solutions  for  the  potassium  dichro- 
mate, or  by  adding  varying  quantities  of  some  iron  salt 
— as  ferrous  sulphate — to  the  Catechu  solution  before 
padding,  and  then  passing  the  cloth,  as  before,  through 
acid  or  alkaline  chromate  solutions.  Experiments  may 
also  be  instituted  to  determine  the  best  mode  of  applying 
other  colouring  matters  in  conjunction  with  Catechu,  in 
order  to  obtain  various  shades  of  colour,  etc. 

Experiments  with  Tannic  Acid. — On  adding  a  solution 
of  tartar  emetic  to  a  solution  of  tannic  acid  (especially  if 
ammonium  chloride  be  added),  a  voluminous  white  pre- 
cipitate is  obtained,  which,  on  experiment,  is  found  to 
possess  the  power  of  attracting  most  of  the  coal-tar  colour- 
ing matters  of  a  basic  character  from  their  solutions, 
and  combining  with  them  to  form  colour-lakes,  insoluble 
even  in  soap  solutions.  With  these  premises,  let  it  be 
supposed  that  it  is  the  object  of  the  dyer  to  determine  by 
a  series  of  experiments  the  most  favourable  conditions  for 
producing  these  colour-lakes  upon  the  cotton  fibre. 

The  method  of  procedure  would  be,  first  of  all,  to  pre- 
pare several  tannin  solutions  of  different  degrees  of  con- 
centration, containing,  for  example,  2'5,  5,  10,  15,  20,  25  g. 
=  38  5,  77*1,  154-3,  231*4,  308  6,  3857  grains  of  technically 
pure  tannic  acid  per  litre  =  0*2  gal.  In  each  of  these  solu- 
tions a  piece  of  calico  should  be  steeped  for  a  definite 
period,  say  6  hours,  and,  after  removing  excess  of  liquid 
by  squeezing,  etc.,  each  piece  should  be  divided  into 
three  portions.  One  portion  of  each  might  be  passed  at 
once — in  its  moist  condition— into  a  solution  of  tartar 
emetic;  a  second  portion  might  be  first  dried;  and  a  third 
portion  might  be  dried  and  steamed  previously.  All  the 
"  swatches  "  might  be  immersed  together  in  the  same  bath, 
if  only  one  is  assured  that  there  is  excess  of  tartar  emetic 
present.  After  J  hour's  immersion  they  should  be 
thoroughly  washed,  to  remove  all  loosely  adhering  pre- 
cipitate, and  then  passed  into  a  solution  of  some  basic 
coal-tar  colouring  matter — as  Methylene  Blue. 


EXPERIMENTS  IN  DYEING. 


135 


The  swatches  are  kept  constantly  stirred  during  im- 
mersion, and  are  thus  dyed  in  the  cold  for  about  ^  hour; 
from  time  to  time  further  slight  additions  of  colour  solu- 
tion are  made ;  the  bath  is  then  gradually  heated  to  about 
60°  C,  and  the  swatches  are  allowed  to  remain  in  the 
solution  until  they  have  acquired  the  maximum  intensity. 

They  are  now  taken  out  and  well  washed,  and  each 
swatch  is  divided  into  two  parts.  One  half  is  dried,  the 
other  is  worked  for  about  J  hour  in  a  soap-bath,  heated  to, 
say,  60°  C,  then  rinsed  in  water  and  dried.  Of  course, 
each  separate  swatch  is  marked  by  holes  cut  near  the 
edge,  in  order  to  distinguish  it  from  the  rest,  and  eventu- 
ally they  should  all  be  pasted  in  a  pattern  book,  and 
references  to  each  should  be  written  at  the  side. 

If  all  the  different  coloured  swatches  are  then  carefully 
compared  with  each  other,  the  following  determinations 
may  be  made  :  — 

1.  The  amount  of  tannic  acid  necessary  to  employ  for 
obtaining  a  definite  shade  of  blue. 

2.  The  beneficial  effect  produced  by  drying  or  steaming 
of  the  tannin-prepared  cotton  is  quantitatively  deter- 
mined, and  it  is  at  once  seen  how  defective  is  the  method 
usually  employed  of  passing  the  material  in  its  damp 
condition  direct  into  the  tartar  emetic  bath.  The  differ- 
ence is  specially  noticeable  in  the  soaped  swatches. 

As  to  the  proper  concentration  of  the  tartar  emetic 
bath  to  be  employed,  this  cannot  be  authoritatively  deter- 
mined on  the  small  scale,  but,  of  course,  the  aim  must 
always  be  to  thoroughly  fix,  or  render  insoluble,  the  whole 
of  the  tannic  acid  present  in  the  fibre.  By  a  few  experi- 
ments on  the  large  scale  it  will  be  easy  to  find  what 
amounts  of  tartar  emetic  must  be  used,  in  order  to  leave 
as  little  excess  as  possible  in  the  fixing-bath.  If  the  goods 
pass  through  the  bath  in  a  continuous  manner,  they  are, 
of  course,  only  immersed  for  a  very  short  time,  and  the 
solution  must  then  be  made  more  concentrated,  and  con- 
tinuously replenished  from  a  stock  solution,  in  order  to 
ensure  the  presence  of  a  slight  excess  of  tartar  emetic. 
Only  by  experiments  made  on  the  large  scale  in  the  dye- 
works  is  it  possible  to  determine  also  what  evil  effects  are 
produced  by  the  passage  of  a  large  number  of  tannin- 
prepared  pieces  through  the  same  tartar  emetic  bath. 


136  COLOURING  MATTERS  FOR  DYEING  TEXTILES 


The  addition  of  such  salts  as  ammonium  chloride,  etc., 
to  the  fixing-bath,  for  the  purpose  of  facilitating  precipita- 
tion, may  also  be  tried. 

One  point  still  remains  to  be  determined,  namely,  the 
proper  temperature  of  the  fixing-bath,  and  this  may  be 
ascertained  by  an  additional  series  of  experiments,  similar 
to  those  instituted  in  the  case  of  fixing  Catechu  by  means 
of  potassium  dichromate. 

Stannic  chloride,  zinc  acetate,  etc.,  also  precipitate  tan- 
nic acid  from  its  solutions,  and  if  on  economical  grounds 
it  is  desired  to  substitute  these  for  tartar  emetic,  the  most 
favourable  conditions  of  concentration,  temperature,  etc., 
with  respect  to  these,  must  be  determined  according  to 
the  above  method.  Finally,  parallel  experiments  must  be 
made  with  the  best  methods  of  employing  the  different 
fixing-agents,  as  previously  determined,  and  the  most  con- 
venient may  then  be  selected. 

Experiments  with  Colouring  Matters. — Should  the 
problem  to  be  solved  relate  to  the  application  of  a  coal-tar 
colour  to  wool  or  silk,  one  must  determine  whether  the 
dyeing  should  take  place  in  a  neutral  or  acid  bath.  In 
the  case  of  silk,  one  may  try  the  utility  of  adding  "  boiled- 
off  "  liquor  to  the  bath,  and,  having  determined  the  best 
amount  to  use,  one  proceeds,  in  the  event  of  an  acid  bath 
being  required,  to  determine  the  proper  kind  and  exact 
amount  of  acid  to  add.  One  may  also  try  the  use  of  acid 
salts — alum,  cream  of  tartar,  etc. — instead  of  free  acid. 
Here,  too,  experiments  must^be  made  to  see  whether  it  is 
better  to  dye  in  a  cold  or  hot  bath,  or  how  high  the  tem- 
perature should  be  raised,  and  in  what  time  the  highest 
limit  of  temperature  should  be  attained,  etc. 

In  some  cases,  an  alkaline  dye-bath  may  be  found  the 
best — as  with  Alkali  Blue — on  wool  and  silk.  Since  both 
these  fibres  are  more  or  less  attacked  by  alkalis,  especially 
under  prolonged  influence  and  at  a  high  temperature,  etc., 
it  becomes  imperative  to  make  experiments  for  the  purpose 
of  choosing  the  least  injurious  form  and  the  minimum 
amount  of  alkali,  also  the  proper  temperature,  duration 
of  boiling,  etc. 

In  studying  the  application  of  such  colouring  matters 
as. require  the  aid  of  mordants,  the  necessary  experimental 
work  becomes  even  more  difficult  than  in  the  cases  already 


EXPERIMENTS  IN  Bit E  WO. 


cited.  The  following  considerations,  for  example,  require 
to  be  taken  into  account  :  1,  the  particular  kind  and 
amount,  or  concentration,  of  mordant  to  employ ;  2,  the 
conditions  of  mordanting — duration,  temperature,  etc.  ; 
3,  the  fixing  of  the  mordant.  As  to  the  subsequent  dyeing, 
the  experiments  partake  of  the  character  of  those  already 
mentioned. 

As  an  illustration  of  the  kind  of  experiments  pursued 
in  respect  of  mordants,  the  application  of  an  aluminium 
salt  to  cotton  and  to  wool  will  now  be  sketched. 

Experiments  in  Mordanting  Cotton. — Cotton  is  scarcely 
ever  mordanted  with  aluminium  sulphate,  but  rather  with 
aluminium  acetate,  for  reasons  which  have  already  been 
given  in  the  chapter  on  Mordants.  The  compound 
A12S04(C2H302)4  will  be  here  considered. 

Several  solutions  containing  this  compound  may  be 
made,  and  of  such  concentration,  for  example,  that  they 
contain  what  is  equivalent  to  10,  20,  40,  60,  80,  100  g.  = 
154*3,  308*6,  617*2,  9259,  1234*5,  1543  2  grains  of  A12(S04)3- 
•18H20  per  litre  =  0'2  gal. 

Separate  pieces  of  calico  or  cotton  yarn  are  impreg- 
nated as  evenly  as  possible  with  each  of  these  solutions, 
and  are  then  exposed  for  about  2  days  to  a  moist,  warm 
atmosphere  in  an  ageing  chamber,  in  order  to  allow  the 
acetic  acid  to  evaporate.  After  such  treatment  there  re- 
mains on  the  fibre  a  basic  salt,  of  the  composition 
A1203*S03,  which,  neglecting  the  water  of  hydration,  may 
also  be  represented  thus  :  A1203*3S03  +  2A1203.  From 
this  it  becomes  evident  that  for  full  and  complete  pre- 
cipitation on  the  fibre,  the  latter  should  be  passed  through 
a  weak  alkaline  bath,  in  order  to  remove  the  sulphuric 
acid  still  present. 

For  this  purpose,  one  may  compare  the  use  of  silicate, 
arsenate,  phosphate,  and  carbonate  of  soda  or  ammonia, 
or  simply  chalk  suspended  in  water,  etc.  Of  these  salts, 
it  is  advisable  to  employ  solutions  of  various  degrees  of 
concentration,  but  containing  equivalent  amounts  of  sub- 
stance. Such  several  solutions  are  used  both  cold  and  at 
a  temperature  of  50°-60°  C.  The  mordanted  cotton  is  well 
worked  therein  for  2-3  minutes,  until  thoroughly  wetted, 
then  washed  well,  and  properly  dyed,  using  a  slight  excess 
of  colouring  matter,  as  Alizarin. 


138  COLOURING  MATTERS  FOE  DYEING  TEXTILES. 


It  is  advisable  to  dye  for  some  time  in  the  cold  solu- 
tion, then  to  raise  the  temperature  slowly,  say  in  the 
course  of  1  hour,  to  60°  C.  If  the  swatches  seem  not  to  take 
up  any  more  colouring  matter — if  the  mordant  is  saturated 
— they  are  well  rinsed  in  water,  and  one  half  of  each  is 
moderately  well  soaped.  After  drying,  the  various 
swatches  are  compared  with  each  other  as  to  colour,  and 
with  a  little  practice  one  is  soon  able  to  determine  which 
flxing-bath  gives,  relatively,  the  best  result.  In  using 
Alizarin,  it  is  well  to  remember  that  the  dye-bath  must 
contain  a  certain  percentage  of  calcium  acetate. 

Experiments  in  Mordanting  Wool. — Since  the  method 
of  mordanting  wool  differs  from  that  employed  for  cotton, 
experiments  on  the  application  of  mordants  to  this  fibre 
assume  another  form.  With  regard  to  aluminium  mor- 
dants, for  example,  the  ordinary  plan  is  to  boil  the  wool 
with  a  solution  of  alum  or  aluminium  sulphate,  with  the 
addition  of  cream  of  tartar,  and  one  has  to  determine 
the  relative  and  absolute  amounts  of  these  constituents 
to  be  employed,  in  order  to  give,  for  example,  the  best 
red  with  Alizarin. 

For  this  purpose,  six  mordanting-baths  are  prepared, 
each  containing,  say,  1  litre  =  0'2  gal.  of  distilled  water, 
and  such  amounts  of  A12(S04)3'18H20  as  are  equal  to  2, 
3,  4,  6,  8,  10  %  of  the  weight  of  wool  employed.  It  is 
convenient  to  take  10  g.  =  154*3  grains  of  wool  for  each 
vessel.  The  mordanting-baths  are  then  simultaneously 
heated,  so  that  their  temperature  may  be  raised  to  the 
boiling  point,  say  in  the  course  of  1  hour,  and  the  wool  is 
boiled  for  i  hour  longer.  The  swatches  are  then  well 
washed  and  dyed  simultaneously  in  separate  baths,  with 
equal  weights  of  Alizarin. 

The  dyeing  is  conducted  in  a  manner  similar  to  that 
given  for  cotton,  but  it  is  here  necessary  that  towards 
the  end  of  the  operation  the  wool  be  boiled.  The  addition 
of  calcium  acetate  to  the  dye-bath  is  also  necessary.  If 
excess  of  Alizarin  has  been  used  in  the  dye-bath,  it  should 
be  removed  by  boiling  the  dyed  swatches  in  distilled  water. 

After  drying,  the  swatches  are  compared  with  each 
other,  and  the  necessary  amount  of  aluminium  sulphate 
to  employ  is  fixed  upon,  say  6-8  %.  A  second  series  of 
mordanting  experiments  should  then  be  made,  in  which 


EXPERIMENTS  IN  DYEING. 


139 


equal  weights  of  wool  are  mordanted,  say  with  6  %  of 
aluminium  sulphate  alone,  and  also  with  the  addition  of 
increasing  amounts  of  cream  of  tartar.  It  is  con- 
venient to  consider  the  amount  of  aluminium  sulphate 
employed  as  representing  1  molecule  of  the  salt,  and  to 
add  the  cream  of  tartar  to  the  several  baths,  in  the  propor- 
tion of  0,  1,  2,  3,  4,  6  molecules.  The  method  of  mordant- 
ing and  dyeing  is  conducted  exactly  as  already  described, 
and  on  comparing  the  colours,  of  the  dyed  swatches,  it  is 
easy  to  determine  whether  or  not  the  addition  of  cream  of 
tartar  to  the  mordanting-bath  has  been  at  all  beneficial, 
and,  if  so,  which  amount  gives  the  best  result. 

Since,  in  the  case  of  wool  and  silk,  the  mordant  may  be 
applied  before,  after,  or  simultaneously  with  the  colouring 
matter,  other  series  of  experiments  must  be  carried  out 
in  order  to  determine  which  of  these  methods  is  the  best. 

In  comparing  the  dyed  swatches,  not  only  is  the  in- 
tensity, purity,  brilliancy,  regularity,  etc.,  of  the  colour 
taken  into  account,  but  also  the  effect  produced  upon  the 
fibre,  and  the  behaviour  of  the  colour  towards  washing, 
soaping,  scouring,  milling,  rubbing,  light,  etc. 

In  all  cases  of  experimental  dyeing,  indeed,  it  is 
essential  to  conduct  the  experiments  under  conditions  as 
similar  as  possible  to  those  which  are  met  with  on  the 
large  scale,  and  in  judging  of  the  results,  great  care  must 
be  taken  to  avoid  the  possibility  of  referring  any  effect 
produced  to  more  than  one  cause  at  a  time. 

To  sum  up  the  whole  system  of  experimenting  on  the 
application  of  colouring  matters  by  dyeing,  it  may  be  said 
that,  in  order  to  determine  the  effect  of  each  particular 
ingredient  used,  the  dyer  must  perform  simultaneously 
two  or  more  distinct  experiments,  in  which  equal  weights 
of  the  same  textile  material  are  submitted  to  all  the  neces- 
sary operations  under  precisely  the  same  conditions,  ex- 
cept as  regards  the  amount  employed  of  the  ingredient 
whose  action  is  to  be  studied. 

Whatever,  indeed,  be  the  factor  the  influence  of  which 
is  to  be  determined,  whether  it  be  the  duration  or  tem- 
perature of  mordanting  or  of  dyeing,  the  character  or 
amount  of  the  several  ingredients  employed,  and  so  on, 
that  factor  alone  is  varied,  while  the  others  remain  un- 
changed.   In  this  way  a  systematic  series  of  dyeing  experi- 


140  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Fig.  19.— Elevation  of  Fig-.  18. 


EXPERIMENTS  IN  DYEING. 


141 


merits  is  carried  out;  one  by  one  the  nature  and  value  of 
each  individual  influence  is  carefully  ascertained,  until  at 
length,  by  a  cumulative  process,  sthe  totality  of  conditions 
necessary  to  produce  the  best  results  is  accurately  deter- 
mined. The  actual  number  of  experiments  which  it  may 
be  requisite  to  perform  with  any  given  colouring  matter, 
before  arriving  at  a  full  knowledge  of  its  dyeing  proper- 
ties, is  quite  indefinite,  and  is  more  or  less  influenced  by 
the  character  of  the  colouring  matter,  and  by  the  general 
and  special  chemical  knowledge  of  the  experimenter. 

Far  too  frequently,  it  is  to  be  feared,  the  dyer  neglects 
or  declines  to  institute  dyeing  experiments  on  the  above 
lines,  but  regards  them  either  as  of  little  use,  or  as  too 
costly,  or  as  taking  up  too  much  time,  ignoring  or  for- 
getting that  the  knowledge  thus  obtained  invariably  leads 
to  almost  absolute  certainty  in  carrying  out  dyeing  opera- 
tions on  the  large  scale,  and  repays  a  thousandfold  the 
time  and  trouble  expended. 

As  to  the  apparatus  required,  it  is  comparatively  sim- 
ple. A  water-  or  steam-bath,  or  an  oil-  or  glycerine-bath, 
heated  with  gas  or  steam,  provided  with  a  perforated  cover 
for  the  reception  of  the  dye-vessels,  serves  for  the  simul- 
taneous and  equable  heating  of  the  latter.  The  dye-vessels 
themselves  should  be  of  toughened  glass  or  well-glazed 
porcelain,  and  capable  of  holding  about  J  litre  or  even 
1  litre  =  0'2  gal.  Metallic  vessels  of  whatever  kind, 
although  very  useful  for  special  work,  are  not  to  be  recom- 
mended for  general  use,  especially  for  experimental  wool- 
dyeing,  since  the  acids  and  acid  salts  so  frequently  used 
in  mordanting  and  dyeing  invariably  dissolve  traces  of  the 
metal  which,  in  many  cases,  affect  the  ultimate  result. 
For  the  same  reason,  stirring-rods  or  other  apparatus  for 
moving  the  textile  material  during  the  mordanting  or 
dyeing  process,  must  also  be  of  glass  or  porcelain.  A 
good  balance,  a  few  glass  beakers,  porcelain  basins, 
measure  glasses,  burettes,  pipettes,  and  hydrometers,  com- 
plete the  equipment. 

Figs.  18  to  20  show  plan,  elevation,  and  section  of  a 
very  convenient  arrangement  for  experimental  dyeing 
(made  by  Messrs.  Broadbent  &  Sons,  Huddersfield).  It 
consists  of  a  couple  of  strong  cast-iron  pipes  b,  into  which 
iron  cups  c?  for  holding  glycerine,  are  screwed.    The  porce- 


142  COLOURING  MATTERS  FOB  DYEING  TEXTILES 


lain  dye-vessels  A  re^t  in  the  glycerine  cups,  and  are 
clamped  down  by  means  of  a  flange,  protected  with  india- 
rubber  or  asbestos  rings.  The  pipes  b  are  so  supported 
that  they  can  be  readily  turned  on  their  axles,  by  means  of 
the  handles  f,  for  the  purpose  of  emptying  the  dye-vessels. 
The  axles  are  hollow,  and  serve  respectively  for  the  intro- 
duction of  steam  at  d,  and  the  escape  of  condensed  water 
at  E.  One  of  the  difficulties  hitherto  encountered  in  ex- 
perimental dyeing  arrangements  is  that  of  being  able  to 
heat  the  water  in  a  series  of  porcelain  dye-vessels  to  the 
boiling  point  simultaneously,  and  in  a  sufficiently  con- 
venient and  cleanly  apparatus.  The  one  here  shown,  in 
which  steam  at  50-60  lb.  pressure  is  used,  will  be  found 
to  answer  every  requirement. 

Exposure  of  Dyed  Patterns  to  External  Influences. — 
Although  in  the  above  reference  has  been  made  to  the 
method  of  determining  the  conditions  of  dyeing,  etc., 
necessary  to  obtain  the  brightest,  most  intense,  and  best 
colours,  it  must  not  be  forgotten  that  a  dyer  knows  but 
half  his  business  if  he  is  simply  acquainted  with  these  con- 
ditions. He  must  not  only  learn  how  best  to  apply  any 
given  colour ;  he  must  also  know  the  capabilities  of  each 
dyed  colour  :  how  it  withstands  the  action  of  light,  mill- 
ing, scouring,  etc. — in  short,  all  those  influences,  whether 
natural  or  artificial,  to  which  the  dyed  fabric  is  likely  to 
be  submitted.  Hence,  all  dyers  should  habitually  and 
systematically  expose  portions  of  dyed  patterns  to  the 
several  influences  just  mentioned,  and,  as  already  stated, 
all  care  must  be  taken  to  avoid  the  possibility  of  referring 
any  effect  produced  to  more  than  one  cause  at  a  time. 
Such  exposed  patterns  must  be  afterwards  carefully  com- 
pared with  the  original  patterns  as  dyed. 

Fastness  of  Colours. — The  term  u  fast  colour  7?  gener- 
ally implies  that  the  colour  in  question  resists  the  fading 
action  of  light,  but  it  may  also  imply  that  it  is  unaffected 
by  washing  with  soap  and  water,  or  by  the  action  of  acids 
and  alkalis,  scouring,  milling,  rubbing,  bleaching,  etc. 
In  its  wide  sense,  it  means  that  the  colour  is  not  affected 
by  any  of  those  influences  to  which  it  is  destined  to  be 
submitted,  but  its  technical  meaning  is  often  restricted. 
To  the  cotton-dyer,  for  example,  it  may  refer  chiefly  to 
washing  with  soap  and  water,  and  to  light,      To  the 


EXPERIMENTS  IN  DYEING, 


U3 


woollen-dyer  it  may  refer  to  milling,  scouring,  and  light; 
and  so  on. 

Many  colours  may  be  fairly  fast  to  washing  with  soap 
and  water,  and  yet  be  very  fugitive  towards  light ;  or  they 
may  be  fast  to  light,  and  yet  very  sensitive  to  the  action 
of  acids  or  alkalis. 

The  term  "  loose  colour  "  generally  implies  that  the 
colour  is  much  impoverished,  or  even  entirely  removed,  by 
washing  with  water  or  a  solution  of  soap ;  it  may,  how- 
ever, also  mean  that  it  is  not  fast  to  light. 

The  word  "  permanent, as  applied  to  colour,  generally 
denotes  that  it  is  fast  to  light  and  other  natural  influences. 

A  "  fugitive  colour  "  is  generally  understood  to  be  one 
which  is  not  fast  to  light,  or  which  volatilises  more  or  less 
under  the  influence  of  heat. 

In  the  absence,  then,  of  any  definite  meaning  being 
attached  to  the  above  terms,  it  becomes  imperative,  in 
speaking  of  the  fastness  of  a  colour,  to  refer  specially  to 
the  particular  influences  which  it  does  or  does  not  resist. 

Influence  of  Light  on  Dyed  Colours. — The  chemical 
activity  of  the  sun's  rays  is  well  known,  and  it  has 
already  been  noticed  that  certain  unstable  mordant  solu- 
tions seem  to  be  decomposed  and  precipitated  more  readily 
under  the  influence  of  light.  It  is  not  surprising,  there- 
fore, to  find  that  light  should  also  have  a  very  marked 
effect  upon  dyed  colours.  Under  the  prolonged  influence 
of  light  and  air  almost  all  colours  fade,  and  according 
to  their  relative  behaviour  in  this  respect,  they  are  broadly 
divided  into  two  classes,  namely,  those  which  are  "  fast  to 
light, "  and  those  which  are  "  not  fast  to  light."  There 
is,  however,  no  definite  line  of  demarcation  between  the 
two,  and  dyed  colours  are  met  with  possessing  all  possible 
degrees  of  resistance. 

Each  of  the  coloured  rays  of  the  spectrum  possesses  a 
different  fading  power.  White  light  is  the  most  active, 
then  follow  the  yellow,  blue,  green,  orange,  violet,  and 
red  rays.  Direct  sunlight  is  more  energetic  than  diffused 
daylight.  The  light  of  the  electric  arc  acts  in  the  same 
sense  as  sunlight,  but  is  less  powerful  (about  one-fourth). 

According  to  Chevreul,  the  presence  of  oxygen  and 
moisture  assists  very  materially  in  the  fading  action 
of  light,  so  that  even  some  fugitive  colours,  dyed,  for 


I 

Ui   COLOURING  MATTERS  FOR  DYEING  TEXTILES. 

example,  with  Safflower,  Annatto,  Orchil,  do  not  fade  if 
exposed  to  light  in  dry  oxygen  or  in  vacuo.  Chevreul 
has  shown,  too,  that  the  nature  of  the  fibre  has  consider- 
able influence  in  the  matter,  and  that  some  colours  are 
less  fugitive  on  cotton  than  if  fixed  on  wool  or  silk. 
Whether  the  essential  action  of  light  is  one  of  oxidation 
or  of  reduction,  or  whether  the  action  varies  with  each 
colouring  matter,  has  not  yet  been  determined.  In  the 
case  of  Prussian  Blue,  it  is  said  to  be  one  of  reduction,  but 
from  the  fact  that  air  and  moisture  play  generally  an 
important  part  in  the  fading  process,  it  is  quite  con- 
ceivable that  in  many  cases  it  is  one  of  oxidation.  It  is 
known  that  during  the  evaporation  of  water,  ozone  or 
hydrogen  peroxide  is  found  in  small  quantities,  and  both 
are  powerful  oxidising,  as  well  as  bleaching,  agents. 

Heat  is  found  to  act  in  some  cases  in  the  same  sense 
as  light,  but  in  a  very  inferior  degree. 

The  following  notes  referring  to  the  fastness  of  colours 
are  taken  from  experiments  made  with  dyed  wool,  samples 
of  which  were  exposed  to  the  light  during  periods  of  1, 
2,  4,  8,  and  12  months. 

The  division  of  the  colouring  matters  into  "  fast," 
"  medium,"  and  "  fugitive  "  is  more  or  less  approximate, 
and  is  merely  intended  to  convey  in  a  simple  manner  the 
general  character  of  each. 

Red  Colours. 

Fast.  Alizarin  (Al),  Isopurpurin,  Purpurin,  Flavo- 
purpurin,  Nitro-alizarin  (Cu),  Madder. 

Medium.  Cochineal  (Sn,  Al),  Biebrich  Scarlet  and 
allied  colours. 

Fugitive.  Many  of  the  Azo  Reds  and  Scarlets,  Ma- 
genta, Safranine,  Aurin,  Eosin,  and  allied 
colours;  Peachwood  (Al,  Sn),  and  allied  red 
woods;  Barwood  (Al,  Sn),  Sanderswood  (Al,  Sn), 
Ammoniacal  Cochineal  (Sn). 

Orange  and  Yellow  Colours. 

Fast.    Iron  Buff,  Chromate  of  lead  yellow,  Canarin, 
Chrysamin  on  cotton  (Bayer),  Orange  G  (m.  l.  & 
b.),  Nitro-alizarin  (Sn,  Al),  Alizarin  (Sn),  Iso- 
purpurin (Sn),  Flavopurpurin  (Sn). 


EXPERIMENTS  IN  DYEING. 


145 


Medium.  Crocein  Orange,  Diphenylamin  Orange, 
/3  Naphthol  Orange,  Azoflavin,  Brilliant  Yellow, 
Fast  Yellow,  other  coal-tar  yellows,  Weld  (Sn), 
Old  Fustic  (Sn),  Quercitron  Bark  (Sn),  Flavin 
(Sn),  Persian  Berries  (Sn). 

Fugitive,  a  Naphthol  Orange,  Chrysoidine,  Phos- 
phine,  Fluorescein,  Turmeric,  Annatto,  Young 
Fustic  (Sn). 

Green  and  Olive  Colours. 

Fast.  Coerulein,  Naphthol  Green,  Persian  Berries 
(Ou). 

Medium.  Weld  (Cu,  Fe),  Old  Fustic  (Cu,  Fe),  Queis 
citron  Bark  (Cu,  Fe),  Flavin  (Cu,  Fe). 

Blue  Colours. 

Fast.    Vat  Indigo,  Alizarin  Blue,  Prussian  Blue. 

Medium.    Logwood  (Cu,  Fe,  Cr),  Indulines. 

Fugitive.  Alkali  Blues,  Soluble  Blues,  Spirit  Blues, 
Indigo  Carmine,  Methylene  Blue  (this  is  very 
much  faster  on  cotton),  Logwood  (Al). 

Purple  Colours. 

Fast.  Alizarin  (Fe,  Cr),  Isopurpurin  (Fe),  Gallcin 
(Cr,  Cu). 

Medium.  Gallein  (Al,  Fe),  Cochineal  (Cr,  Fe),  Gallo- 
cyanin. 

Fugitive.  Logwood  (Sn),  Ammoniacal  Cochineal  (Al), 
Orchil,  Limawood  (Cr,  Fe),  Methyl  Violet,  Hof- 
mann's  Violet,  Perkin's  Violet,  Rosaniline  Violet. 

Brown  Colours. 

Fast.  Nitro-alizarin  (Cr),  Isopurpurin  (Cr,  Cu), 
Flavopurpurin  (Cr,  Fe,  Cu),  Purpurin  (Cr,  Fe, 
Cu),  Madder  (Cr,  Fe,  Cu),  Cochineal  (Cu), 
Catechu. 

Medium.    Camwood  (Cu,  sadden). 

Fugitive.  Camwood  (Cr,  Cu,  Al,  mordant  and  dye), 
Barwood  (Cr,  Cu),  Sanderswood  (Cr,  Cu),  Bis- 
marck Brown,  other  Azo  Browns. 

_  Some  colouring  matters— as  Alizarin— give  fast  colours 
with  all  mordants;  others— as  Limawood  and  Young  Fustic 
J 


146  COLOURING  MATTERS  FOR  DYEING  TEXTILES 


— seem  only  capable  of  yielding  fugitive  colours;  others 
again — as  Logwood — give  fast  or  fugitive  colours,  accord- 
ing to  the  mordant  employed.  The  fugitive  character  of 
the  colours  obtained  from  Logwood  by  the  use  of  tin  and 
aluminium  mordants,  compared  with  the  medium  fastness 
of  those  obtained  when  copper,  chromium,  or  iron  mor- 
dants are  employed,  is  rather  striking. 

Some  colours  present  somewhat  abnormal  properties. 
Wool  mordanted  with  aluminium  and  tin  mordants,  and 
dyed  with  Camwood,  yields  reddish-brown  colours,  which 
during  exposure  become  at  first  considerably  darker,  and 
begin  to  fade  only  after  2  or  4  months.  The  olive-green 
colour  yielded  by  Persian  Berries  and  copper  sulphate 
is  quite  remarkable  in  this  respect,  since  it  actually 
becomes  darker  and  greener,  even  after  an  exposure  of 
12  months.  The  pure  greenish-yellow  obtained  with 
Picric  Acid  exhibits  a  similar  character  ;  on  exposure  it 
rapidly  becomes  orange,  and  this  begins  to  fade  only  after 
a  lapse  of  about  12  months. 

The  mode  of  application  also  influences  the  fastness  of 
the  colour.  Camwood  and  Catechu,  for  example,  yield 
faster  colours  with  copper  sulphate  by  the  saddening 
method  than  by  the  mordanting  and  dyeing  method. 

In  studying  the  behaviour  of  the  coal-tar  colours  to- 
wards light,  one  cannot  fail  to  be  struck  with  the  manifest 
influence  of  their  chemical  constitution  in  the  matter. 
All  those  colouring  matters,  for  example,  in  which  the 
atomic  arrangement  is  like  that  of  Magenta,  are  similarly 
fugitive  to  light — as  Methyl  Violet,  Benzaldehyde  Green, 
etc.  ;  such  similarity  extends  even  to  Aurin  and  Safranine. 
Colouring  matters  allied  to  Alizarin,  on  the  other  hand, 
all  possess  the  quality  of  fastness  to  light.  There  are, 
however,  cases  in  which  an  apparently  slight  difference  in 
constitution  gives  rise  to  remarkable  differences  in  fast- 
ness to  light — compare,  for  example,  Fluorescein  and 
Gallein,  Indigo  Carmine  and  Vat  Indigo  Blue. 

The  popular  fallacy  that  coal-tar  colours  are  fugitive, 
and  that  the  colours  yielded  by  dyewoods  are  fast,  has 
already  been  shown  to  be  false,  and  is  only  referred  to 
because  it  still  lingers  in  the  minds  of  some  dyers.  The 
origin  of  a  colouring  matter  has,  of  course,  nothing  what- 
ever to  do  with  its  properties  :  these  are  mainly,  if  not 


EXPERIMENTS  IN  DYEING. 


147 


entirely,  governed  by  its  chemical  composition  and  con- 
stitution. 

Dyeing  Compound  Shades. — Comparatively  few  of  the 
colours  met  with  on  dyed  fabrics  result  from  the  employ- 
ment of  a  single  colouring  matter.  Therefore  it  becomes 
imperative  for  the  dyer  to  know  how  to  apply  two  or  more 
together.  This  knowledge  can  readily  be  gained  by 
making  a  series  of  dyeing  experiments.  The  result  ob- 
tained by  mixing,  as  it  were,  the  dyed  colours  must  be 
observed  and  studied  much  in  the  same  way  as  the  artist 
does  with  the  pigments  upon  his  palette. 

None  of  the  colours  here  dealt  with  are  pure,  like 
those  of  the  physicist;  hence  the  product  of  the  mixture 
of  dyed  colours  is  for  the  most  part  totally  different  from 
what  would  be  produced  by  combining  together  the  various 
colours  of  the  spectrum. 

A  mixture  of  red  and  yellow  produces  orange,  yellow 
and  blue  produce  green,  blue  and  red  produce  violet, 
green  and  violet  produce  blue.  Orange  and  green  tend 
to  produce  yellow ;  violet  and  orange  tend  to  produce  red. 

The  compound  colours,  orange,  green,  and  violet,  vary 
in  shade  according  to  the  amount  and  purity  of  tone  of 
each  constituent  single  colour.  If,  for  example,  in  com- 
bining yellow  and  blue,  the  yellow  inclines  to  orange,  or 
the  blue  inclines  to  purple,  the  green  produced  inclines 
to  olive. 

With  the  physicist,  white  is  produced  either  by  a  mix- 
ture of  all  the  colours  of  the  spectrum,  or  by  mixing 
together  what  are  known  as  "  complementary  colours," 
for  example,  the  following  : — 

Purple  and  green. 
Red  and  bluish-green. 
Orange  and  turquoise  blue. 
Yellow  and  ultramarine  blue. 
Yellowish-green  and  violet. 

With  the  dyer,  however,  the  opposite  effect  tends  to  be 
produced.  A  judicious  mixture  of  red,  yellow,  and  blue 
tends  to  produce  sombre  colours  or  even  black.  In  the 
same  way  red  and  green  produce  chocolate  or  brown, 
blue  and  orange  produce  drab,  etc. 

It  is  beyond  the  scope  of  this  manual  to  discuss  the 
law  of  the  mixture  of  colours.    For  information  on  this 


148   COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


point  the  reader  is  referred  to  Bezold's  "  Theory  of 
Colour/7  Rood's  "  Modern  Chromatics,"  and  other  simi- 
lar works.  It  is,  however,  always  imperative,  in  the  end, 
to  gain  positive  and  reliable  information  by  actually 
making  special  dyeing  experiments,  and  even  then,  long 
experience  is  required  before  one  feels  thoroughly  at  home 
in  producing  any  given  compound  shade. 

A  very  necessary,  or  at  least  desirable,  point  to  remem- 
ber is  that  all  the  colouring  matters  employed  simul- 
taneously should  be  really  applicable  to  the  best  advantage 
by  the  same  process.  A  colouring  matter  which  requires 
to  be  applied  in  an  acid-bath  ought  not  to  be  applied 
simultaneously  with  one  which  dyes  best  in  a  neutral  bath. 
Basic  colouring  matters,  although  not  requiring  mor- 
dants, can,  however,  be  frequently  employed  along  with 
such  as  do,  whenever  the  "  mordanting  and  dyeing 
method  "  is  used,  since  the  latter  are  almost  invariably 
applied  in  a  neutral  dye-bath. 

If  the  compound  shade  is  intended  to  be  fast  towards 
any  influence — as  light,  milling,  etc. — then  each  constitu- 
ent colour  yielded  by  the  several  dyestuffs,  when  separately 
employed,  should  be  as  similar  in  fastness  to  that  influ- 
ence as  possible. 

Although  dyers  frequently  apply  fast  and  fugitive 
colours  together  in  producing  compound  shades,  or  for 
the  sake  of  improving  the  brilliancy  of  any  given  colour, 
it  is  always  more  or  less  irrational,  and  ought  to  be 
avoided  whenever  possible. 

Influence  of  Milling. — The  process  of  "  milling,"  so 
much  used  in  the  heavy  woollen  trade  for  Tweeds,  etc., 
consists  in  saturating  the  woollen  cloth  with  a  strong  solu- 
tion of  soap  (frequently  carbonate  of  soda  as  well)  and 
then  submitting  it  to  a  violent  kneading,  beating,  or 
pressing,  in  the  wash-stocks  or  "milling  machine."  It 
is  an  exceptionally  severe  treatment,  and  demands  of  the 
colour  :  that  it  shall  withstand  rubbing,  that  it  shall  not 
be  decomposed  by  or  be  soluble  in  weak  alkalis,  and  that 
whatever  colour  does  rub  off,  this  shall  not  permanently 
stain  contiguous  fibres  (bleeding).  As  a  general  rule, 
the  best  colouring  matters  in  respect  of  the  last  point 
are  those  which  require  the  aid  of  mordants,  as  Alizarin, 
Logwood,    etc.     Coal-tar    colours,    which    are  applied 


EXPERIMENTS  IN  DYEING. 


149 


directly — as  Magenta,  Azo  Scarlets,  etc. — are  very  prone 
to  dissolve  off  and  dye  the  neighbouring  fibres. 

Some  acid-colours  are  unsuitable  because  they  are  more 
or  less  decolorised  by  the  action  of  the  alkali,  as  Acid 
Magenta,  Acid  Green,  Alkali  Blue,  Alkali  Green,  etc. 
In  such  cases  the  original  colour  can  be  more  or  less 
restored  by  a  passage  through  dilute  acid,  preferably 
acetic  acid. 


150 


CHAPTER  X. 

ESTIMATION   OF   THE   VALUE   OF   COLOURING  MATTERS. 

In  order  that  the  dyer  may  produce  good  and  regular 
work,  it  is  essential  that  the  conditions  under  which  he 
labours  shall  be  maintained  as  regular  as  possible.  The 
mordants  and  colouring  matters  he  employs  should  be  of 
good  quality,  free  from  injurious  admixture,  and  of  con- 
stant composition. 

The  certainty  of  obtaining  such  requisites  can  only 
be  relied  upon  by  exercising  constant  care  and  supervision 
in  their  selection,  which  should  always  be  based  on  the 
results  of  analysis  or  practical  experiment. 

The  purity  and  value  of  mordants  can,  as  a  rule,  be 
determined  by  the  ordinary  methods  of  chemical  analysis ; 
not  so,  however,  with  colouring  matters,  since  their  ana- 
lytical behaviour  has  been  for  the  most  part  neglected. 

Colorimetry. — The  rapid  determination  of  the  com- 
parative colouring  power  of  any  given  colouring  matter, 
by  means  of  the  colorimeter,  has  only  partially  and  in- 
adequately solved  the  problem,  and  it  has  in  most  cases 
little  practical  value. 

The  instrument  consists  of  two  calibrated  tubes  of 
equal  diameter  and  length,  into  which  are  put  the  solu- 
tions of  equal  weights  of  the  two  colouring  matters  to  be 
compared  with  each  other.  As  a  rule,  one  solution 
appears  darker  than  the  other,  and  this  must  be  diluted 
with  some  of  the  solvent  until  both  solutions  are  equal 
in  intensity  of  colour.  The  colouring  powers  of  the  two 
dyestuffs  are  proportionate  to  the  volumes  of  the  diluted 
solutions. 

One  difficulty  which  presents  itself  is  that  a  fair  com- 
parison can  only  be  made  when  the  colouring  matters 
under  examination  are  free  from  coloured  impurities, 
and  are  exactly  of  the  same  tint. 

Comparative  Dye-Trials.— The  most  practical  and 
satisfactory  method  of  estimating  the  relative  value  of 


VALUE  OF  GO  LOURING  MATTERS.  151 


colouring  matter  is  to  make  a  series  of  comparative  dyeing 
experiments  on  a  small  scale. 

In  these  experiments  the  fibre  dyed  should  be  the 
same  as  that  to  which  eventually  the  colouring  matter  is 
to  be  applied,  and,  as  far  as  possible,  exactly  the  same 
process  of  dyeing,  and  all  necessary  subsequent  operations 
should  be  adopted  as  are  employed  on  the  large  scale. 

When  it  is  desired  to  choose  the  best  sample  from  a 
number  of  colouring  matters  which  are  offered  for  sale, 
equal  weights  of  cotton-,  wool-,  or  silk-yarn  are  dyed  with 
equivalent  values  of  the  several  samples,  in  which  case 
that  sample  which  gives  the  best  results  is  of  course  the 
cheapest,  whatever  its  actual  price  may  be. 

It  is  advisable  that  comparative  dye-trials  of  this 
kind  should  be  made  with  all  the  colouring  matters  in 
general  use,  and  samples  of  the  best  and  cheapest  (i.e. 
those  adopted)  should  be  carefully  preserved  in  stoppered 
bottles,  to  serve  as  "  standards,"  or  "  types." 

Aged  or  moist  dyewoods  (e.g.  Logwood)  should  be 
previously  dried,  to  prevent  deterioration.  It  afterwards 
becomes  necessary  to  test  in  a  similar  manner  all  subse- 
quent deliveries  of  each  colouring  matter,  and  to  com- 
pare them  with  their  respective  "  standards." 

One  essential  condition  of  success  in  making  compara- 
tive dye-trials  is  that  the  several  portions  of  yarn  or  cloth 
should  be  dyed  simultaneously,  and  under  exactly  the 
same  conditions  as  to  time,  temperature,  etc.  The  most 
convenient  dye-bath  arrangement  is  that  consisting  of 
six  or  eight  glazed  porcelain  or  hardened  glass  dye- 
vessels,  each  of  250°-1000°  cm3  =  15'2-61'0  cubic  inches 
capacity,  immersed  in  a  common  water-,  oil-,  or  glycerine- 
bath,  suitably  heated  by  gas  or  steam,  or  the  arrangement 
illustrated  on  p.  140. 

Ground  dyewoods,  after  weighing,  may  be  at  once  put 
into  the  dye-vesse]s,  but  it  is  best  first  to  prepare  solutions 
of  extracts,  pastes,  or  soluble  colouring  matters,  particu- 
larly if  of  high  colouring  power  (as  coal-tar  colours). 
For  example,  01-1  g.  —  2-15'4  grains  is  dissolved  in 
100  cm5  =  61  cubic  inches  of  water  or  alcohol,  and  the 
requisite  quantity  of  solution  is  introduced  into  the  dye- 
vessel  by  means  of  a  pipette. 

Swatches  of  cloth  are  distinguished  from  each  other  by 


152  COLOURING  MATTERS  FOB  DYEING  TEXTILES. 


cutting  small  holes  near  the  edges;  yarn  is  marked  by 
means  of  knotted  threads.  After  filling  the  dye-vessels 
with  cold  water  first,  the  colouring  matter  is  introduced, 
then  the  cloth  or  yarn,  previously  wetted  with  water. 
It  is  well,  as  a  rule,  to  dye  for  some  time  in  the  cold, 
in  order  to  ensure  perfectly  even  dyeing;  and  then,  with 
constant  stirring,  to  raise  the  temperature  gradually,  or 
exactly  as  one  would  do  on  the  large  scale. 

After  dyeing,  the  swatches  are  washed  and  dried;  or 
if  necessary  a  portion  of  each  may  be  worked  for  \  hour 
or  so  in  a  hot  soap  solution,  or  otherwise  cleansed  and 
brightened,  and  then  washed  and  dried. 

The  patterns  are  finally  compared  with  each  other 
under  exactly  similar  conditions  of  illumination.  Blue, 
violet,  and  green  colours  are  frequently  more  accurately 
judged  of  by  gaslight. 

For  those  engaged  in  cotton-dyeing,  it  is  convenient 
to  employ  in  the  above  trials  calico  printed  with  various 
mordants,  in  the  form  of  broad  stripes — as  with  iron  and 
aluminium  mordant  separately — each  in  two  degrees  of 
concentration,  and  also  with  a  mixture  of  the  two.  Such 
mordanted  calico  was  originally  in  general  use  for  testing 
the  commercial  value  of  Madder,  but  it  can  be  very  con- 
veniently used  in  testing  all  those  dyestuffs  which  are 
used  in  practice,  in  conjunction  with  the  above  mordants, 
for  the  production  of  serviceable  colours,  as  the  various 
dyewoods  or  their  extracts,  Alizarin,  Gallein,  etc. 

For  those  colouring  matters  which  can  be  fixed  by 
means  of  tannic  acid,  it  is  convenient  to  use  calico  padded 
or  printed  in  stripes  with  tannic  acid,  and  afterwards 
fixed  in  a  tartar  emetic  bath,  washed  and  dried. 

For  the  woollen-  and  silk-dyer,  it  is  best  to  dye  equal 
weights  of  these  materials,  either  in  form  of  yarn  or 
cloth.  Whenever  necessary  they  are  first  mordanted,  and 
all  the  ingredients  which  it  is  necessary  to  employ  on 
the  large  scale  are  added  to  the  dye-bath. 

The  most  difficult  colouring  matters  to  estimate  are 
those  which  cannot  be  exhausted  in  the  dye-bath;  with 
such,  dyers  often  dip  white  blotting-paper  or  calico,  as 
equally  as  possible,  into  the  solutions.  It  is  allowed  to 
drain,  and  then  dry,  and  a  comparison  of  the  colours  on 
the  stained  paper  is  made. 


VALUE  OF  COLOURING  MATTERS.  153 


In  certain  cases,  fractional  dyeing  gives  information 
as  to  foreign  matter  or  impurities  present  in  a  colouring 
matter.  A  concentrated  dye-bath  is  prepared,  01  m.  = 
4  inches  of  cloth  is  dyed  in  it,  and  after  its  removal  a 
second,  third,  fourth,  etc.,  are  dyed  in  the  remaining 
solution,  until  the  bath  is  exhausted.  If  the  colouring 
matter  is  pure,  the  different  swatches  should  not  vary 
in  tone,  although  they  may  do  so  in  intensity. 

The  purification  of  certain  colouring  matters  by  the 
manufacturer  entails  considerable  loss.  The  cheaper 
qualities  of  Rosaniline  Blue  always  contain  reddish-violet 
colouring  matter ;  hence  a  pure  blue  (6  B)  gives  a  weaker 
colour  than  the  cheaper  reddish-blues.  For  certain  pur- 
poses, the  latter  are  indeed  preferable  to  the  former,  as 
for  the  production  of  compound  shades. 

The  dyer  is  strongly  recommended  not  to  be  deterred 
from  making  exact  dyeing  trials  because  of  the  (compara- 
tively little)  trouble  they  give,  for  he  will  only  in  this 
manner  properly  estimate  the  worth  of  his  dyestuffs,  and 
avoid  irregular  or  bad  work. 

It  is  probable  that  if  the  testing  of  dyestuffs  before 
using  them  were  only  generally  adopted,  the  custom  would 
cease  of  mixing  or  diluting  colouring  matters  with  useless 
bodies— as  dextrin,  sugar,  sand,  etc. — which  has  been 
forced  upon  the  colour  manufacturer,  because  of  want  of 
judgment,  on  the  part  of  many  dyers,  who  wish  only  to 
buy  cheap. 

In  order  to  recognise  the  individual  colouring  matters, 
one  makes  all  possible  use  of  the  reactions  dependent 
upon  their  chemical  properties. 

Mixtures  of  colouring  matters  are  recognised  some- 
times by  the  following  methods  :  A  strip  of  white  blotting- 
paper  is  partly  immersed  in  the  solution,  when  it  fre- 
quently happens  that  the  different  colouring  matters 
exhibit  different  degrees  of  capillary  adhesion,  and 
different  zones  of  colour  are  perceptible  on  the  paper ;  or 
a  little  of  the  finely-powdered  colouring  matter  is  dusted 
over  white  blotting-paper,  moistened  with  water  or  other 
suitable  solvent,  or  it  is  dusted  over  a  glass  vessel  con- 
taining the  solvent  in  a  perfectly  still  condition.  If  the 
colouring  matter  is  a  mixture,  differently-coloured  spots 
appear  on  the  paper,  or  streaks  of  the  different  colour 


154  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


solutions  are  seen  in  the  solvent.  Such  an  appearance  is 
well  shown  by  coal-tar  colour  mixtures,  intended  to  give 
indigo-blue  shades  :  they  give  violet,  orange,  and  green 
spots  or  streaks.  It  is  also  conceivable  that  the  different 
constituents  of  a  colour  mixture  are  not  all  soluble  in  the 
same  solvent — a  fact  which  may  also  serve  to  differentiate 
them. 

Chemical  methods  of  estimating  the  value  of  colour- 
ing matters  cannot  always  be  accepted  as  wholly  reliable. 
As  a  rule,  standard  solutions  of  oxidising  agents  are 
employed — as  bleaching-powder,  potassium  chlorate  or 
dichromate  in  acid  solution,  or  potassium  ferrocyanide  in 
alkaline  solution — and  these  are  added  until  the  colour  is 
destroyed. 

These  and  other  methods  will  be  found  in  works  on 
chemical  analysis. 


INDEX. 


Acid,  Amido-azo-sulphonic,  85-88 

 ,  Green,  applied  to  Silk,  52 

 ,   ,           ■         Wool,  52 

  Magenta,  53,  54 

 .   ■  applied  to  Silk,  54 

 .    .     Wool,  53,  54 

•  ,  Picric  (see  Picrid  Acid) 

 ,  Rosolic,  76 

 ,  Tannic,     Experiments  with, 

134-136 

 ,  Violet,  59 

Alizarin,  96-124 

  applied  to  Cotton,  97-121 

—  Wool,  121-124 

 Blue,  125,  126 

    applied  to  Cotton.  125 

 Silk,  126 

 — -    Wool,  125,  126 

 ,  Experiments  with,  138 

■         Orange  applied  to  Wool,  122 

 Pinks,  119 

 ■  Purples,  119,  120 

  Red  applied  to  Wool,  121 

  -,  Dyeing  Cotton  with,  119 

Aldehyde  Green,  71 
Alkali  Blue,  56 

 applied  to  Wool,  56,  57 

■  Silk,  58 

  Green,  52,  53 

  Violet,  59,  60 

Aluming,  Process  of,  102 
Aluminium  Salt  applied  to  Cotton 

and  Wool,  137 
Amaranth,  93 
Amido-azo-colours,  84,  85 
Amido-azo-sulphonic  Acids,  85-88 
Aniline  Black  applied  to  Cotton, 

66-71 

 Silk  and  Wool, 

71 

    Dyeing  Machine,  68 

 Dyes,  66-71 

  Colouring  Matters,  50-71 

  Colours    containing  Sulphur, 

71 

  Yellow,  84 

Anisol  Red,  93 
Annatto,  48 

Anthracene  Colouring  Matters,  96- 
126 

■        Green,  80-82 

  Violet,  79 

Azarins,  89,  90 
Azo  Blue,  90 

 Colouring  Matters,  84-95 

Azoflavin,  87 
Auramine,  61 

■         applied  to  Cotton,  61 

 Silk,  61 

 Wool,  61 

Aurantia,  75 
Aureosin,  77 
Aurin,  76 
Barberry,  49 
Bark,  Quercitron,  48 


Barwood,  47 

Basf  referred  to,  59-62 

Bayer  and  Co.,  References  to,  74, 

88,  89,  90,  91,  92,  94 
Bengal,  Rose,  77 

Berlin  Aniline  Co.,  References  to, 
72,  87,  91,  93,  94 

Benzaldehyde  Green,  50 

    applied  to  Cotton,  51 

 ■  Silk,  51,  52 

 Wool,  51 

Benzopurpurin,  88 

Benzylrosaniline  Violet,  59 

Berries,  Persian,  48,  49 

Bichromate  of  Potash,  Experiment- 
ing with,  37 

Biebrich  Scarlet,  93 

Black  on  Boiled-off  Silk,  43-46 

 ,  Bonsor's,  40,  41 

■  ,  Chrome,  35,  36 

 ,  Dead,  35,  36 

 ,  Direct,  40 

 ,  Dyeing  Tussur  Silk,  46 

  Dyes,  Aniline,  66-71  (see  also 

Aniline  Black) 

 ,  English,  44 

 ,  Ferrous  Sulphate,  39,  40 

  for  Hat  Plush,  43 

—  Trimmings,  Mason's, 

43,  44 

 ,  Heavy,  45 

 ,  Logwood,  31-34 

— — ,  Lyons,  44 

 ,  Mineral,  44 

 on  Raw  Silk,  46 

 Silk,  Gillet's  Methods  of  Dye- 
ing, 43 

  Souples,  Fine,  45,  46 

  for  Tussur  Silk,  46 

 ,  Violet,  35 

 for  Velvets,  44 

 ,  Watine-Delespierre's,  40 

 ,  Woaded,  41 

Blue,  Alizarin,  125,  126  (see  also 
Alizarin  Blue) 

 ,  Alkali  (see  Alkali) 

 ,  Azo,  90 

 Colours,  Characters  of,  145 

  D,  New,  65 

 ,  Dark,  Dyeing  Cloth,  28 

 ,  Diphenylamine,  54 

 ,  Ethyl,  54 

— ,  Fluorescent,  75 

 ,  Indigo  Carmine,  10 

 ,  Logwood,  35 

 ,  Methyl,  54 

 ,  Methylene     (see  Methylene 

Blue) 

 ,  Naphtbol,  82,  83 

 ,   ,  applied  to  Cotton,  83 

 ;   1  —  Wool,  83 

 ,  Napoleon's,  131 

 ,  Night,  62 

 ,  Prussian,    128-131    (see  also 

Prussian  Blue) 


156   COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Blue,  Quinoline,  72 

 ,  Resorcin,  applied  to  Silk,  75 

 ,  Raymond's,  130 

 ,  Rosaniline,  54 

 ,   ,  Purification  of,  153 

 ,  Saxony,  29 

 ,  Soluble,  55,  56 

 ,   ,  applied  to  Cotton,  55,  56 

 ,  Spirit,  54 

 ,  Victoria,  62 

  for  Wool,  Logwood,  41,  42 

Boiled-off  Silk,  Black  on,  43-46 
Bonsor's  Blacks,  40,  41 
Brazilwood,  47 

Broadbent's  Dyeing  Apparatus  for 

Experiments,  141,  142 
Brook,  Reference  to,  58 
Brown  Colours,  Characters  of,  145 

 ,  Fast,  92 

— ,  Manganese,  128 
 ,  Orchil,  89 

 ,  Phenyl  (see  Phenyl  Brown) 

 ,  Phenylene,  85  (see  also  Pheny- 

lene  Brown) 
Briining,  References  to,  59,  72 
Buff,  Iron,  127 

Calvert   on   Sediments   in  Indigo 

Vats,  15 
Campobello  Yellow,  74 
Camwood,  47 

 ,  Properties  of,  146 

Carmine  Blue,  Indigo,  10 
 ,  Indigo,  29 

Casella  and  Co.,  References  to,  65, 

75,  82,  84,  85,  87,  91,  93 
Catechu,  49 

 ,  Experiments  with,  132-134 

 ■  Tannin  Matter,  32 

Chevreul    on    Fading    Action  of 

Light,  143,  144 
Chrome  Black,  35,  36 

    on  Cotton,  Obtaining,  33 

 Yellow,  127 

Chrysamin,  90 
Chrysoidine,  84,  85 

  applied  to  Cotton,  84 

 Silk,  85 

 Wool,  84,  85 

Chrysolin  Dyes,  76 

Claret  Red  B,  92,  93 

Cloth,  Distinguishing  Swatches  of, 

151,  152 
 ,  Dyeing,  27 

   ,  Sulphated    Oil  Process 

for  Dyeing,  111 

   ,  Turkey-red  (see  Turkey- 
red) 

Coal-tar  Colours,  Influence  of  Light 

on,  146 
Coccin,  77 

 ,  New,  93 

Coccinin  B,  93 

Cochineal,  47,  48 

Ccerulein  applied  to  Cotton,  80 

 ■  Silk,  82 

  .  Wool,  81,  82 

  Dyes,  80-82 

Colorimetry,  150 


Colouring  Matters,  Aniline,  50-71 

 ,  Anthracene,  96-126 

   ,  Azo,  84-95 

   ,  Experiments  with,  136 

 ,  Indigo,  9-30 

   ,  Logwood,  31-46 

   ,  Oxy-azo,  88-95 

   ,  Mixtures    of,  Recognis- 
ing, 153,  154 

 ,  Natural  Red,  47-49 

 ,  Phenol,  72 

 ,  Quinoline,  72 

 ,  Value  of,  150,  154 

 ,  Yellow,  47-49 

Colours,  Fastness  of,  142,  143 
Complementary  Colours,  147 
Compound  Shades,  Dyeing,  147,  148 
Congo  Red  applied  to  Cotton.  87,  88 

 Silk  and  Wool, 

88 

Cotton,  Alizarin  applied  to,  97-121 

 ,   ■  Blue  applied  to,  125 

 ,  Aluminium  Salts  applied  to, 

137 

 ,  Aniline  Black  applied  to,  66-71 

 ,  Auramine  applied  to,  61 

 ,  Benzaldehyde  Green  applied 

to,  51 

— -,  Chrysoidine  applied  to,  84 

 ,  Ccerulein  applied  to,  80 

 ,  Eosins  applied  to,  78 

 ,  Gallein  applied  to,  79 

 ,  Gallocyanin  applied  to,  83 

 ,  Hofmann's  Violet  applied  to, 

58 

 ,  Indigo  applied  to,  10-17 

 ,           Vats  for  Dyeing,  11-17 

 ,  Indulines  applied  to,  63 

 ,  Logwood  applied  to,  31-35 

 ,  Methyl  and  Ethyl  applied  to, 

54,  55 

— ,  Green  applied  to,  60 

 ,  Methylene  Blue  applied  to,  71 

 ,  Mordanting,  Experiments  in, 

137 

 ,  Naphthol  Blue  applied  to,  83 

 ,  New  Blue  D  applied  to,  65 

 ,  Obtaining  Chrome  Black  on, 

33 

 ,  Oxy-azo   Colours   applied  to, 

94 

 ,  Phenylene  Brown  applied  to, 

85 

 ,  Prussian  Blue  applied  to,  128, 

129 

 ,  Rosaniline  Violet  applied  to, 

58 

•  ,  Safranine  applied  to,  65 

Crocein,  Brilliant,  93 

 .  3  BX,  92 

 •  Scarlet,  94 

Crystal  Scarlet  6  R,  93 

 •  Violet,  62 

Cyanosin,  78 
Dead  Blacks,  35,  36 
Dimethylaniline  Orange  applied  to 

Cotton,  86 
 Wool,  86 


INDEX. 


157 


Diphenylamine  Blue,  54 

 ■  Orange,  86,  87 

"  Direct  Black,"  40 
Durand,  References  to,  77,  83 
Dye-bath,  Action  of  Lime  Salts  in, 
118 

Dyed  Colours,  Influence  of  Light 
on,  143 

—  Patterns,  External  Influences 
on,  142 

Dyeing  Apparatus  for  Experi- 
ments, Broadbent's,  141,  142 

  Cloth,  Sulphated  Oil  Process 

for,  111 

 ■  Compound  Shades,  147,  148 

 ,  Experiments  in,  132-149 

 ■  with  Indigo  Vat,  26-29 

 ,  Indigo  (see  Indigo  Dyeing) 

  Machine    for    Cotton  Aniline 

Black,  68 

 ■  Tussur  Silk  Blaok,  46 

 ■  Woollen  Cloth,  27 

 ■   ■  Material     with  Indigo 

Vat,  26 

 Yarn,  27 

Dyes,  Aniline  Black,  66-71 

 ,  Chrvsolin,  76 

 ,  Ccerulein,  80  82 

 ,  Eosin,  77 

 ,  Fluorescein,  76 

— ,  Gallein,  79 

 ,  Indophenol,  82,  83 

 ,  Induline,  63-65 

 ,  Oranin,  76 

 ,  Phthaleins,  76 

 ,  Rosaniline,  50  63 

 ,  Trials  for,  150-154 

Dye-trials,  Comparative,  150,  151 

Dyewoods,  Ground,  151 

Emulsion    Process    of  Turkey-red 

Yarn  Dyeing,  97-107 
Endler,  Reference  to,  128 
English  Black,  44 
Eosin,  77 

 ■  applied  to  Cotton,  78 

■ —  ■  Silk,  79 

 •  •  Wool,  79 

 ■  B  N,  77 

 •  Dyes,  77 

Ethyl  Blue,  54 
— -  Purple,  62 

Experiments  in  Dyeing,  132-139 
External  Influences  on  Dyed  Pat- 
terns, 142 
Extract,  Indigo,  9,  29 
Fast  Brown.  92 

—  Red,  92 
 •  Red  B,  93 

  Yellow  applied  to  Silk,  86 

 Wool,  86 

Fastness  of  Colours,  142,  143 

- — -   ■   ,  Notes  on,  144,  145 

Ferrous  Sulphate  Blacks,  39,  40 
 ^or   Inc*igo  Dyeing, 

Flavaniline,  72 
Flavin,  48 

Fluorescein  Dyes,  76 


Fluorescent  Blue,  75 

"  Fugitive    Colour,"  Explanation 

of,  143 
Fustic,  Old,  48 

 ,  Young,  48 

Gallein  applied  to  Cotton,  79 

 ■  Wool,  79,  80 

 ■  Dyes,  79 

Gallocyanin  applied  to  Cotton,  83 

 Wool,  83 

Garanein  supplanted  by  Turkey- 
red  Dye,  97 

German  Vat  for  Indigo  Dyeing,  20, 
21 

Gillet's  Methods  of  Dyeing  Silk, 
43-45 

Girard,  Reference  to,  77 
Green,  Acid,  52 

 ,  Aldehyde,  71 

 ,  Alkali,  52,  53 

 ,  Anthracene,  80-82 

■  ,  Benzaldehyde  (see  Benzalde- 

hyde  Green) 

 •  Colours,  Characters  of,  145 

 ,  Methyl  (see  Methyl  Green) 

 ,  Naphthol,  75,  76 

 ,   ,  applied  to  Wool,  76 

Greys,  Logwood,  34 

Grinding  Mills  for  Indigo,  10 

Ground  Dyewoods,  151,  152 

Hat  Trimming,  Mason's  Black  for, 

43,  44 

Hawking  Machine  used  in  Cloth 

Dyeing,  27,  28 
Heavy  Black,  45 
Heliochrysin,  75 
Hofmann's  Violet,  58 

    applied  to  Cotton,  58 

 ■  ■  Silk,  58,  59 

 Wool,  58 

Huguenin,  References  to,  77,  83 
Hydrosulphite     Vat     for  Indigo 

Dyeing,  17,  21-25 

  Liquor,  Preparing,  22,  23  ' 

Indian  Yellow,  87 

Indigo  applied  to  Cotton,  10-17 

 Wool,  17-30 

  Carmine,  29 

 Blue,  10 

  Colouring  Matters,  9-30 

 Dyeing,  Ferrous  Sulphate  Vat 

for,  11-15 

   ,  German  Vat  for,  20,  21 

 ,  Hydrosulphite    Vat  for, 

17,  21-25 

    Machine,     Mather  and 

Piatt,  14 

 — ,  Potash  Vat  for,  20 

 ,  Soda  Vat  for,  20,  21 

   ,  Theory  of,  9,  10 

 ,  Urine  Vat  for,  21 

 ,  Woad  Vat  for,  18-20 

   ,  Zinc  Powder  Vat  for,  15- 

17 

  Extract,  9,  29 

 •  applied  to  Silk,  30 

 Wool,  29,  30 

 Grinding  Mills,  10 


158  COLOURING  MATTERS  FOR  DYEING  TEXTILES. 


Indigo  Substitute,  26,  37 
  Vat,  17,  18 

 ■   ,  Calvert  on  Sediment  on, 

15 

—    for  Cotton  Dyeing,  11 

 ,  Defects  in,  25,  26 

 ■  ,  Dyeing  with,  26-29 

Indophenol  Dyes,  82,  83 
Induline  Dyes,  65-65 
Indulines  applied  to  Cotton,  63 

 Silk,  64 

 Wool,  63,  64 

Iron  Buff,  127 

 ,  Pyrolignite  of,  32 

Isopurpurin,  117 
Kalle  and  Co.,  Reference  to,  93 
Liechti,  References  to,  107,  113,  117, 
118 

  and  Suida's  Experiments  on 

Lime-salts,  118 
Light,  Chevreul  on  Fading  Action 

of,  143 

  on  Dyed  Colours,  Influence  of, 

143 

Limawood,  47 

Lime  Salts  in  Dye-bath,  Action  of, 
118 

 ,  Liechti  and  Suida's  Ex- 
periments on,  118 

Liquor-padding  Machine  for  Tur- 
key-red Dyeing,  Stewart's,  109, 
110 

Logwood,  Preventing  Deterioration 
of,  151 

 applied  to  Cotton,  31-35 

 .         Silk,  43-46 

 Wool,  35-43 

  Blacks,  31-34 

 Blues,  35 

 for  Wool,  41,  42 

 ■  Colouring  Matters,  31-46 

 Greys,  34 

 Purples,  34 

— -    for  Wool,  42 

"  Loose  Colour  "  Explained,  143 
Lucius,  References  to,  59,  72 
Lutecienne,  77 
Lyons  Black,  44 
Madder,  47 
Magenta,  52 

 ,  Acid,  53,  54 

Manganese  Brown,  128 

Mather  and  Piatt  Indigo  Dyeing 

Machine,  14 
Meister,  References  to,  59,  72 
Metanil  Yellow,  87 
Methyl  Blue,  54 

  and  Ethyl  applied  to  Cotton, 

54,  55 

 Silk,  55 

 r—  Wool,  55 

 ■  Green,  60,  61. 

    applied  to  Cotton,  60 

■  ■  Silk,  61 

— ■  Wool,  60 

 Violet,  59 

Methylene  Blue,  71 

    applied  to  Cotton,  71 


Methylene  Blue  applied  to  Wool,  71 
"  Milling,"  Influence  of,  148,  149 
Mills  for  Grinding  Indigo,  10 
Mineral  Black,  44 
Monnet,  References  to,  77,  78 
Mordanting    Cotton,  Experiments 
in,  137,  138 

  Wool,  Experiments  in,  138-142 

Naphthalene  Pink  applied  to  Silk,  64 
Naphthol  Blue,  82,  83 

 ■    applied  to  Cotton,  83 

 Wool,  83 

  Green,  75-76 

  applied  to  Wool,  76 

 ■  Orange,  90,  91 

 ■  Yellow  applied  to  Silk,  74 

 Wool,  74 

Napoleon's  Blue,  131 
Naphthyiamine  Violet,  71 
Neutral  Reel,  65 

New  Blue  D  applied  to  Cotton,  65 
Night  Blue,  62 

Nitro  Compounds  of  Phenol,  72-75 
Nitro-alizarin,  124,  125 

  applied  to  Wool,  124 

Nitrous  Acid  on  Phenols,  Action 

of,  75 
Nopalin,  77 

Oil    used   in   Turkey-red  Dyeing, 
105,  107 

Oil-padding  Machine  for  Turkey- 
red  Dyeing,  Stewart's,  108 

Olive  Colours,  Characters  of,  145 

Orange  Colours,  Characters  of,  144 

 ,  Dimethylaniline,    applied  to 

Cotton,  86 

 ,  ,  Wool,  86 

 •,  Diphenylamine,  86,  87 

 •  G,  91 

— ,  Naphthol,  90,  91 
— ,  Palatine,  75 

Oranin  Dyes,  76 

Orchil,  48 

 ■  Brown,  89 

Oxy-azo  Colouring  Matters,  88-95 

 ■  Colours  applied  to  Cotton,  94 

 Silk,  95 

  ■     Wool,  94,  95 

Palatine  Orange,  75 
Peachwood,  47 
Perkin's  Violet,  63 
"Permanent"  Denned,  143 
Persian  Berries,  48,  49 

  — ,  Properties  of,  146 

Phenetol  Red,  93 

Phenol  Colouring  Matters,  72- 

 ,  Nitro  Compounds  of,  72-75 

Phenols,  Action    of    Nitrous  Acid 
on,  75 

Phenyl  Brown  applied  to  Silk,  73 

 Wool,  73 

Phenylene  Brown,  85 

  applied  to  Cotton,  85 

 ■    Silk,  85 

  ■  Wool,  85 

Phloxin,  77 
Phosphine,  62,  63 
Phthalems  Dyes,  76 


INDEK. 


159 


Picric  Acid,  72,  73 

— —    applied  to  Silk,  73 

■  Wool,  72 

   ,  Properties  of,  146 

Pink,  Alizarin,  119 

 ,  Naphthalene,  applied  to  Silk, 

64,  65 

Poirrier,  References  to,  77,  89,  90,  92 
Potash  Bichromate,  Experimenting 

with,  37 

 ■  Vat  for  Indigo  Dyeing,  20 

Prussian  Blue  applied  to  Cotton, 

128,  129 

 Silk,  130.  131 

 Wool,  129,  130 

Purple,  Alizarin,  119,  120 

  Colours,  Characters  of,  145 

 ,  Ethyl,  62 

 ,  Logwood,  34 

 ,  ,  for  Wool,  42,  43 

Pyrolignite  of  Iron,  32 
Quercitron  Bark,  48 
Quinoline  Blue,  72 

 ■  Colouring  Matters,  72 

 ■  Yellow,  72 

Raw  Silk,  Black  on,  46 
Raymond's  Blue,  130 
Red,  Anisol,  93 

  B,  Claret,  93 

 ,  Fast,  93 

  Colouring    Matters,  Natural, 

47 

 ■  Colours,  Characters  of,  144 

 ,  Congo,  87,  88  (see  also  Congo 

Red) 

 ,  Fast,  92 

 ,  Neutral,  65 

 ,  Phenetol,  93 

Resorcin  Blue,  75 

  applied  to  Silk,  75 

Resorcinol  Yellow,  89 
Rosaniline  Blues,  54 

 ,  Purification  of,  153 

  Dyes,  50 

  Violet,  58 

    applied  to  Cotton,  58 

 Wool,  58 

Rose  Bengal,  77 
Rosolane,  63 

Rosolic  Acid  Colours,  76 
Rubeosin,  77 
Safflower,  48 

Safranine  applied  to  Cotton,  65 
Sanderswood,  47 
Saxony  Blue,  29 
Scarlet,  Biebrich,  93 

 ,  Brilliant,  93 

 ,  Crocein,  94 

 ,  Fast,  94 

 ,  G  G,  91 

  G  T,  91 

—  3  R,  92 

  4  R,  92 

  5  R,  93 

  6  R,  93 

  6  R  Crystal,  93 

 R  R,  92 

  S,  93 


Scarlet  S  S,  94 

 ,  Xylidine,  91 

Silk,  Acid  Green  applied  to,  52 

 ,           Magenta  applied  to,  54 

 ,  Alizarin  Blue  applied  to,  126 

 ,  Alkali  Blue  applied  to,  58 

 ,  Aniline  Black  applied  to,  71 

- — ,  Auramine  applied  to,  61 
 ,  Benzaldehyde   Green  applied 

to,  51,  52 

 ,  Boiled-ofT,  Black  on,  43-46 

 ,  Chrysoidine  applied  to,  85 

 ,  Ccerulein  applied  to,  82 

 ,  Eosins  applied  to,  79 

 ,  Fast  Yellow  applied  to,  86 

 ,  Gillet's   Methods    of  Dveing, 

43-45 

 ,  Hofmann's  Violet  applied  to, 

58,  59 

 ,  Indigo  Extract  applied  to,  30 

 ,  Indulines  applied  to,  64 

 ,  Logwood  applied  to,  43-46 

 ,  Methyl  and  Ethyl  applied  to, 

55 

 ,  Green  applied  to,  61 

 ,  Naphthalene  Pink  applied  to, 

64,  65 

 ,  Naphthol  Yellow  applied  to, 

74 

 ,  New  Yellow  applied  to,  75 

 ,  Oxy-azo  Colours  applied  to,  95 

 ,  Phenyl  Brown  applied  to,  73 

 ,  Phenylene  Brown  applied  to, 

85 

 ,  Prussian  Blue  applied  to,  130, 

131 

 ,  Raw,  Black  on,  46 

 ,  Resorcin  Blue  applied  to,  75 

 ,  Tussur,  Black  Dyeing  of,  46 

 •,  Viridin  applied  to,  52 

Simpson,  Reference  to,  58 

Soda  Vat  for  Indigo  Dyeing,  20,  21 

Soluble  Blues,  55,  56 

—    applied  to  Cotton,  55,  56 

Souples,  Fine  Black,  45,  46 
Spiller,  Reference  to,  58 
Spirit  Blues,  54 

Steaming  Chest  for  Turkey-red 
Yarn,  Stewart's,  115,  116 

      Turkey-red  Yarn, 

Tulpin's,  115 

Steiner's  Process  for  Turkey-red 
Cloth  Dyeing,  107-111 

Stewart's  Liquor-padding  Machine 
for  Turkey-red  Dyeing,  109 

 Oil-padding      Machine  for 

Turkey-red  Dyeing,  108 

  Steaming  Chest  for  Turkey-red 

Yarn,  115,  116 

 ■  Yarn  Wringing  Machine  for 

Turkey-red  Dyeing,  99 

Stove,  Turkey-red,  110 

Suida,  References  to,  113,  117,  118 

Sulphated  Oil  Process  for  Cloth 
Dyeing,  111 

Sulphur,  Aniline  Colours  Contain- 
ing, 71 

Sumaching,  Process  of,  102 


160  COLOURING  MATTERS 


FOR  DYEING  TEXTILES. 


Swatches  of  Cloth,  Distinguishing, 

151,  152 
Tannic  Acid,  134-136 
Tannin  Matter,  Catechu,  32 
Trapcelin,  91 
Trials  for  Dyes,  150-154 
^Tropcelin  Y,  89 
Tulpin's  Steaming  Chest,  Uj 
Turkey-red  Cloth  Dyeing,  steiner' 

Process  for,  107-111 

 ■  Dyeing,  Oil  used  in,  105,  107 

 ■   ,  Stewart's  Liquor-paddir 

Machine  for,  109 
 ■   ,   ■  Oil-padding  MachiiK 

for,  108 
 Stove,  110 

  Yarn  Dyeing,  Emulsion  Pro- 
cess of,  97-107 

  ,  Processes  for,  97 

   ,  Stewart's  Steaming  Chest 

for,  115,  116 

   ,  Tulpin's  Steaming  Chest 

for,  115 

 ■  ,  Weser's  Tramping  Ma- 
chine for,  99 

   ■  Wringing  Machine,  99 

Turmeric,  49 

Tussur  Silk,  Dyeing,  Black,  46 
Urine  Vat  for  Indigo  Dyeing,  21 
Vat  for  Dyeing  Indigo,  13-30 

  ■  Cotton  Indigo,  11-17 

- — Ferrous  Sulphate,  11-15 

 -,  German,  20,  21 

 ,  Hydrosulphite,  17,  21-25 

 ,  Indigo,  17,  18 

 ,   ,  Defects  in,  25  29 

 -,  — Dyeing  with,  26-29 

 ,  Liquor,  Hydrosulphite,  22-25 

 ,  Potash,  20 

 ,  Soda,  20,  21 

 ,  Urine,  21 

 ,  Woad,  18-20 

■  ,  Zinc  Powder,  15-17 

Vat-blue,  9,  10 
Velvets,  Black  for,  44 
Victoria  Blue,  62 

  Yellow,  73,  74 

Violet,  Acid,  59,  60 

 ,  Alkali,  59 

 ,  Anthracene,  79 

 ,  Benzylrosaniline,  59 

  Blacks,  35 

 ,  Crystal,  62 

 ,  Hofmann's,  58,  59 

— Methyl,  59 

 ,  Naphthylamine,  71 

 ,  Perkin's,  63 

 ,  Rosaniline,  58 

Viridin,  52,  53 

 ,  Application  of,  52 

Watine-Delespierre's  Black,  40 
Weld,  48 

Weser's  Tramping  Machine,  98 
Willm  B.  and  Girard,  77 
Woad  Vat  for  Indigo  Dyeing,  18-20 
Woaded  Blacks,  41 


Wool,  Acid  Green  applied  to,  52 

  Magenta  applied  to,  53,  54 

Alizarin  applied  to,  121-124 

 ■  Blue  applied  to,  125,  126 

  Orange  on,  122 

  Red  on,  121 

Alkali  Blue  applied  to,  56,  57 
Aniline  Black  applied  to,  71 
Auramine  applied  to,  61 
Benzaldehyde  Green  applied 
to,  551 

Chrysoidine  applied  to,  84,  85 
Ccerulein  applied  to,  81,  82 
Eosins  applied  to,  79 
Fast  Yellow  applied  to,  86 
Gallem  applied  to,  79,  80 
Gallocyanin  applied  to,  83 
Hofmann's  Violet  applied  to, 
58 

Indigo  Extract  applied  to,  29 
Indulines  applied  to,  63,  64 
Logwood  applied  to,  35-43 

  Blues  for,  41,  42 

  Purples  for,  42,  43 

Methyl  and  Ethyl  applied  to, 
55 

  Green  applied  to,  60 

Methylene  Blue  applied  to,  71 
Mordanting,  138-142 
Naphthol  Blue  applied  to,  83 

  Green  applied  to,  76 

 ■  Yellow  applied  to,  74 

New  Yellow  applied  to,  74 
Nitro-Alizarin  applied  to,  124 
Oxy-azo  Colours  applied  to,  94 
Phenyl  Brown  applied  to,  73 
Phenylene  Brown  applied  to, 
85 

Prussian  Blue  applied  to,  129 
Rosaniline  Violet  applied  to, 
58 

  Viridin  applied  to,  53 

Woollen  Cloth,  Dyeing,  27 

   ,  Hawking  Machine  used 

in  Dyeing,  27,  28 

■         Materials,  Dyeing,  26 

  Yarn,  Dyeing,  27 

Xylidine  Scarlets.  91 
Yarn,  Dyeing,  27 

 1  Turkey-red  (see  Turkey- 

red) 

Yellow,  Aniline,  84 

 ,  Brilliant,  87 

— ,  Campobello,  74 
—-,  Chrome,  127 
—  Colouring  Matters,  47-49 
—  Colours,  Characters  of,  144 

Fast,  85,  86 
— .  Indian,  87 
•  — .  Metanil,  87 

 ,  Naphthol,  74 

— ,  New,  74,  75 
— ,  Quinoline,  72 
— ,  Resorcinol,  89 
-,  Victoria,  73,  74 
Z  ic  Powder  Vats,  15-17 


Printed  by  Cassell  &  Company,  Limited,  Ludgate  Hill,  London,  E.C. 


ROPER'S 
Practical  Hand -Books 

For  Engineers  and  Firemen. 


NEW  REVISED  AND  ENLARGED  EDITION. 

HANDY-BOOK  FOR  STEAM  ENGINEERS 


AND  ELECTRICIANS. 
PRICE,  $3.50. 

price. 

Roper's  Catechism  for  Steam  Engineers  and  Electric- 
ians,  $2*00 

Roper's  Questions  and  Answers  for  Steam  Engineers 

and  Electricians,  2.00 

Roper's  Hand-Book  of  Land  and  Marine  Engines,  ■  3*50 
Roper's  Care  and  Management  of  the  Steam  Boiler,  2,00 
Roper's  Use  and  Abuse  of  the  Steam  Boiler,  .  .  .  .  2.00 

Roper's  Young  Engineers'  Own  Book,  2*50 

Roper's  Hand-Book  of  the  Locomotive,  2*50 

Roper's  Instructions  and  Suggestions  for  Engineers 

and  Firemen,  2*00 

Roper's  Hand-Book  of  Modern  Steam  Fire  Engines, .  3*50 


DAVID  MCKAY,  Publisher, 

610  South  Washington  Square,  Philadelphia. 


Complete  Descriptive  Circulars  Mailed  Free  on  Application. 
Send  for  them* 


TECHNICAL  INSTRUCTION. 


Important  New  Series  of  Practical  Volumes.  Edited  by  PAUL  N.  HASLUCK. 
With  numerous  Illustrations  in  the  Text.  Each  book  contains  about  1 60  pages, 
crown  8vo.    Cloth,  $1.00  each,  postpaid. 

Practical  Draughtsmen's  Work.    With  226  Illustrations. 

Contents. — Drawing  Boards.  Paper  and  Mounting.  Draughtsmen's  Instruments. 
Drawing  Straight  Lines.  Drawing  Circular  Lines.  Elliptical  Curves.  Projection. 
Back  Lining  Drawings.  Scale  Drawings  and  Maps.  Colouring  Drawings.  Making  a 
Drawing.  Index. 

Practical  Gasfitting.    With  120  Illustrations. 

Contents. — How  Coal  Gas  is  Made.  Coal  Gas  from  the  Retort  to  the  Gas  Holder. 
Gas  Supply  from  Gas  Holder  to  Meter.  Laying  the  Gas  Pipe  in  the  House.  Gas 
Meters.  Gas  Burners.  Incandescent  Lights.  Gas  Fittings  in  Workshops  and  Theatres. 
Gas  Fittings  for  Festival  Illuminations.    Gas  Fires  and  Cooking  Stoves.  Index. 

Practical  Staircase  Joinery.    With  215  Illustrations. 

Contents. — Introduction:  Explanation  of  Terms.  Simple  form  of  Staircase — Housed 
String  Stair:  Measuring,  Planning,  and  Setting  Out.  Two-flight  Staircase.  Staircase 
with  Winders  at  Bottom.  Staircase  with  Winders  at  Top  and  Bottom.  Staircase  with 
Half-space  of  Winders.  Staircase  over  an  Oblique  Plan.  Staircase  with  Open  or  Cut 
Strings.  Cut  String  Staircase  with  Brackets.  Open  String  Staircase  with  Bull-nose 
Step.    Geometrical  Staircases.     Winding  Staircases.    Ships'  Staircases.  Index. 

Practical  Metal  Plate  Work.    With  247  Illustrations. 

Contents. — Materials  used  in  Metal  Plate  Work.  Geometrical  Construction  of  Plane 
Figures.  Geometrical  Construction  and  Development  of  Solid  Figures.  Tools  and 
Appliances  used  in  Metal  Plate  Work.  Soldering  and  Brazing.  Tinning.  Re-tinning, 
and  Galvanising.  Examples  of  Practical  Metal  Plate  Work.  Examples  of  Practical 
Pattern  Drawing.  Index. 

Practical  Graining  and  Marbling.    With  79  Illustrations. 

Contents. — Graining:  Introduction,  Tools  and  Mechanical  Aids.  Graining  Grounds 
and  Graining  Colors.  Oak  Graining  in  Oil.  Oak  Graining  in  Spirit  and  Water  Colours. 
Pollard  Oak  and  Knotted  Oak  Graining.  Maple  Graining.  Mahogany  and  Pitch-pine 
Graining.  Walnut  Graining.  Fancy  Wood  Graining.  Furniture  Graining.  Imitating 
Woods  by  Staining.  Imitating  Inlaid  Woods.  Marbling:  Introduction,  Tools,  and 
Materials.    Imitating  Varieties  of  Marble.  Index. 

Painters'  Oils,  Colors  and  Varnishes.    With  Numerous  Illustrations. 

Contents. — Painters'  Oils.  Color  and  Pigments.  White  Pigments.  Blue  Pigments. 
Chrome  Pigments.  Lake  Pigments.  Green  Pigments.  Red  Pigments.  Brown  and  Black 
Pigments.  Yellow  and  Orange  Pigments.  Bronze  Colors.  Driers.  Taint  Grinding  and 
Mixing.    Gums,  Oils,  and  Solvents  for  Varnishes.    Varnish  Manufacture.  Index. 

Practical  Plumber's  Work.    With  298  Illustrations. 

Contents. — Materials  and  Tools  Used.  Solder  and  How  to  Make  It.  Sheet  Lead  Work- 
ing.   Pipe  Bending.    Pipe  Jointing.    Lead  Burning.    Lead-work  on  Roofs.  Index. 

Practical  Pattern  Making.    With  300  Illustrations. 

Contents. — Foundry  Patterns  and  Foundry  Practice.  Jointing-up  Patterns.  Finishing 
Patterns.  Circular  Patterns  Making  Core-Boxes.  Coring  Holes  in  Castings.  Patterns 
and  Moulds  for  Iron  Columns.  S team-Engine  Cylinder  Patterns  and  Core-Boxes.  Worm 
Wheel  Pattern.  Lathe-bed  Patterns.  Headstock  and  Poppet  Patterns.  Slide-reat 
Patterns.    Miscellaneous  Patterns  and  Core-boxes.  Index. 


TECHNICAL  INSTRUCTION  {Continued). 


Practical  Handrailing.    With  144  Illustrations. 

Contents. — Principles  of  Handrailing.  Definition  of  Terms.  Geometrical  Drawing. 
Simple  Handrails.  Wreathed  Handrails  on  the  Cylindrical  System.  The  Uses  of  Models. 
Obtaining  Tangents  and  Bevels.  Face  Moulds :  their  Construction  and  Use.  Twisting 
the  Wreath.  Completing  the  Handrail.  Orthogonal  or  Right-angle  System  of  Setting 
Wreathed  Handrails.  Handrails  for  Stone  Stairs.  Setting  out  Scrolls  for  Handrails. 
Setting  out  Moulded  Caps.  Intersecting  Handrails  without  Basements.  Index. 
Practical  Brickwork.    With  368  Illustrations. 

Contents. — English  and  Flemish  Bonds.  Garden  and  Boundary  Walls.  Bonds  for 
Square  Angles.  Excavations,  Foundations,  and  Footings.  Junctions  of  Cross  Walls. 
Reveals,  Piers.  Angles  and  other  Bonds.  Jointing  and  Pointing.  Damp-proof  Courses 
and  Construction.  Hollow  or  Cavity  Walls.  Chimneys  and  Fireplaces.  Gauged  Work 
and  Arches.  Niches  and  Domes.  Oriel  Windows. 
Practical  Painters'  Work.    With  Numerous  Illustrations. 

Contents. — Objects,  Principles  and  Processes  of  Painting.  Painters'  Tools  and  Appli- 
ances. Materials  used  by  Painters.  Paint  Mixing.  Preparing  Surfaces  for  Painting, 
Painting  Woodwork,  Painting  Ironwork,  Painting  Stucco  or  Plaster;  Distempering 
and  Whitewashing  Color  Combination.  House  Painting.  Varnish  and  Varnishing.  Stains 
and  Staining.    Estimating  and  Measuring  Painters'  Work.  Index. 

Other  Volumes  in  Preparation 
DAVID  McKAY,  Publisher,  Washington  Square,  Philadelphia. 


3  3125  00027 


1 


! 

ft 


i 


